bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024‒04‒07
fifty-nine papers selected by
Viktor Korolchuk, Newcastle University
  1. Autophagosome turnover requires Arp2/3 complex-mediated maintenance of lysosomal integrity.
  2. Mechanistic insights into fasting-induced autophagy in the aging heart.
  3. Infectious bronchitis virus (IBV) triggers autophagy to enhance viral replication by activating the VPS34 complex.
  4. Mitophagy and spermatogenesis: Role and mechanisms.
  5. Exquisite visualization of mitophagy and monitoring the increase of lysosomal micro-viscosity in mitophagy with an unusual pH-independent lysosomal rotor.
  6. Faa1 membrane binding drives positive feedback in autophagosome biogenesis via fatty acid activation.
  7. ULK/Atg1: phasing in and out of autophagy.
  8. Metformin protects against vascular calcification through the selective degradation of Runx2 by the p62 autophagy receptor.
  9. Autophagy dysregulation via the USP20-ULK1 axis in the HERC2-related neurodevelopmental disorder.
  10. Crosstalk between m6A modification and autophagy in cancer.
  11. Role of autophagy and proteostasis in neurodegenerative diseases: Exploring the therapeutic interventions.
  12. LC3B labeling of the parasitophorous vacuole membrane of Plasmodium berghei liver stage parasites depends on the V-ATPase and ATG16L1.
  13. Function of autophagy genes in innate immune defense against mucosal pathogens.
  14. Regulatory mechanisms of autophagy on DHA and carotenoid accumulation in Crypthecodinium sp. SUN.
  15. mTORC1 - TFEB pathway was involved in sodium arsenite induced lysosomal alteration, oxidative stress and genetic damage in BEAS-2B cells.
  16. Neuroprotective mechanisms of luteolin in glutamate-induced oxidative stress and autophagy-mediated neuronal cell death.
  17. Identification and structural characterization of small molecule inhibitors of PINK1.
  18. The Parkinson's disease risk gene cathepsin B promotes fibrillar alpha-synuclein clearance, lysosomal function and glucocerebrosidase activity in dopaminergic neurons.
  19. PINK1 deficiency alters muscle stem cell fate decision and muscle regenerative capacity.
  20. HSPA8 chaperone complex drives chaperone-mediated autophagy regulation in acute promyelocytic leukemia cell differentiation.
  21. Chronic replication stress invokes mitochondria dysfunction via impaired parkin activity.
  22. Collapse of late endosomal pH elicits a rapid Rab7 response via V-ATPase and RILP.
  23. Recent advancement of autophagy in polyploid giant cancer cells and its interconnection with senescence and stemness for therapeutic opportunities.
  24. Epigenetic Reprogramming of Autophagy Drives Mutant IDH1 Glioma Progression and Response to Radiation.
  25. Autophagy Modulation in Endothelial Hyperglycemia-Induced Wound-Healing Impairment.
  26. ATF6 supports lysosomal function in tumor cells to enable ER stress-activated macroautophagy and CMA: impact on mutant TP53 expression.
  27. Autophagy and exosomes; inter-connected maestros in Alzheimer's disease.
  28. PLD3 and PLD4 synthesize S,S -BMP, a key phospholipid enabling lipid degradation in lysosomes.
  29. Proximal tubular MBD2 promotes autophagy to drive the progression of AKI caused by vancomycin via regulation of miR-597-5p/S1PR1 axis.
  30. LC3B conjugation machinery promotes autophagy-independent HIV-1 entry in CD4+ T lymphocytes.
  31. Low-dose cadmium telluride quantum dots trigger M1 polarization in macrophages through mTOR-mediated transcription factor EB activation.
  32. The matrix protein of lyssavirus hijacks autophagosome for efficient egress by recruiting NEDD4 through its PPxY motif.
  33. Role of Macrophage PIST Protein in Regulating Leishmania major Infection.
  34. RNF213 variant and autophagic impairment: A pivotal link to endothelial dysfunction in moyamoya disease.
  35. Mapping the interplay of immunoproteasome and autophagy in different heart failure phenotypes.
  36. Common and divergent molecular mechanisms of fasting and ketogenic diets.
  37. Targeting NKAα1 to treat Parkinson's disease through inhibition of mitophagy-dependent ferroptosis.
  38. The autophagy protein, ATG14 safeguards against unscheduled pyroptosis activation to enable embryo transport during early pregnancy.
  39. Autophagic-lysosomal damage induced by swainsonine is protected by trehalose through activation of TFEB-regulated pathway in renal tubular epithelial cells.
  40. Fraxetin pretreatment alleviates cisplatin-induced kidney injury by antagonizing autophagy and apoptosis via mTORC1 activation.
  41. VCP Inhibition Augments NLRP3 Inflammasome Activation.
  42. MicroRNA-144-3p Inhibits Host Lipid Catabolism and Autophagy by Targeting PPARα and ABCA1 During Mycobacterium Tuberculosis Infection.
  43. Coculture with Colon-26 cancer cells decreases the protein synthesis rate and shifts energy metabolism towards glycolysis dominance in C2C12 myotubes.
  44. Inflammation-induced sialin mediates nitrate efflux in dysfunctional endothelium affecting NO bioavailability.
  45. mTOR Inhibition Prolongs Survival and Has Beneficial Effects on Heart Function After Onset of Lamin A/C Gene Mutation Cardiomyopathy in Mice.
  46. Characterization of Bitter Taste Receptor-Dependent Autophagy in Oral Epithelial Cells.
  47. NRSN2 promotes the malignant behavior of HPV-transfected laryngeal carcinoma cells through AMPK/ULK1 pathway mediated autophagy activation.
  48. Gut microbiota-derived butyrate restores impaired regulatory T cells in patients with AChR myasthenia gravis via mTOR-mediated autophagy.
  49. USP26 promotes colorectal cancer tumorigenesis by restraining PRKN-mediated mitophagy.
  50. Interplay of p62-mTORC1 and EGFR signaling promotes cisplatin resistance in oral cancer.
  51. PGC-1α regulates the interplay between oxidative stress, senescence and autophagy in the ageing retina important in age-related macular degeneration.
  52. SIRT3 alleviates painful diabetic neuropathy by mediating the FoxO3a-PINK1-Parkin signaling pathway to activate mitophagy.
  53. Dietary fasting and time-restricted eating in Huntington's disease: therapeutic potential and underlying mechanisms.
  54. Role of mitochondria in renal ischemia-reperfusion injury.
  55. Targeting the EGFR pathway: An alternative strategy for the treatment of tuberous sclerosis complex?
  56. Ibudilast Protects Retinal Bipolar Cells from Excitotoxic Retinal Damage and Activates the mTOR Pathway.
  57. Combination treatment with ferroptosis and autophagy inducers significantly inhibit the proliferation and migration of oral squamous cell carcinoma.
  58. AP39 through AMPK-ULK1-FUNDC1 pathway regulates mitophagy, inhibits pyroptosis, and improves doxorubicin-induced myocardial fibrosis.
  59. Rapamycin vs TORin-1 or Gleevec vs Nilotinib: Simple chemical evolution that converts PAK1-blockers to TOR-blockers or vice versa?
  1. bioRxiv. 2024 Mar 13. pii: 2024.03.12.584718. [Epub ahead of print]
    Autophagosome turnover requires Arp2/3 complex-mediated maintenance of lysosomal integrity.
    Corey J Theodore, Lianna H Wagner, Kenneth G Campellone.
      Autophagy is an intracellular degradation process that maintains homeostasis, responds to stress, and plays key roles in the prevention of aging and disease. Autophagosome biogenesis, vesicle rocketing, and autolysosome tubulation are controlled by multiple actin nucleation factors, but the impact of actin assembly on completion of the autophagic pathway is not well understood. Here we studied autophagosome and lysosome remodeling in fibroblasts harboring an inducible knockout (iKO) of the Arp2/3 complex, an essential actin nucleator. Arp2/3 complex ablation resulted in increased basal levels of autophagy receptors and lipidated membrane proteins from the LC3 and GABARAP families. Under both steady-state and starvation conditions, Arp2/3 iKO cells accumulated abnormally high numbers of autolysosomes, suggesting a defect in autophagic flux. The inability of Arp2/3 complex-deficient cells to complete autolysosome degradation and turnover is explained by the presence of damaged, leaky lysosomes. In cells treated with an acute lysosomal membrane-damaging agent, the Arp2/3-activating protein WHAMM is recruited to lysosomes, where Arp2/3 complex-dependent actin assembly is crucial for restoring intact lysosomal structure. These results establish the Arp2/3 complex as a central player late in the canonical autophagy pathway and reveal a new role for the actin nucleation machinery in maintaining lysosomal integrity.
    DOI:  https://doi.org/10.1101/2024.03.12.584718
  2. World J Cardiol. 2024 Mar 26. 16(3): 109-117
    Mechanistic insights into fasting-induced autophagy in the aging heart.
    Hannaneh Parvaresh, Katarzyna Paczek, Md Abdul Alim Al-Bari, Nabil Eid.
      Autophagy is a prosurvival mechanism for the clearance of accumulated abnormal proteins, damaged organelles, and excessive lipids within mammalian cells. A growing body of data indicates that autophagy is reduced in aging cells. This reduction leads to various diseases, such as myocardial hypertrophy, infarction, and atherosclerosis. Recent studies in animal models of an aging heart showed that fasting-induced autophagy improved cardiac function and longevity. This improvement is related to autophagic clearance of damaged cellular components via either bulk or selective autophagy (such as mitophagy). In this editorial, we summarize the mechanisms of autophagy in normal and aging hearts. In addition, the protective effect of fasting-induced autophagy in cardiac aging has been highlighted.
    Keywords:  Aging; Autophagy; Fasting; Heart; Mitophagy
    DOI:  https://doi.org/10.4330/wjc.v16.i3.109
  3. Microb Pathog. 2024 Apr 02. pii: S0882-4010(24)00105-0. [Epub ahead of print] 106638
    Infectious bronchitis virus (IBV) triggers autophagy to enhance viral replication by activating the VPS34 complex.
    Gaojie Song, Cuiling Zhang, Xiaoyang Yu, Jiaqi Li, Qinlei Fan, Fei Liu, Qinghao He, Chao Shang, Xiao Li.
      Autophagy plays an important role in the lifecycle of viruses. However, there is currently a lack of systematic research on the relationship between Infectious Bronchitis Virus (IBV) and autophagy. This study aims to investigate the impact of IBV on autophagy and the role of autophagy in viral replication. We observed that IBV infection increased the expression of microtubule-associated protein 1 light chain 3, a marker of autophagy, decreased the expression of sequestosome 1, and led to elevated intracellular LC3 puncta levels. These findings suggest that IBV infection activates the autophagic process in cells. To investigate the impact of autophagy on the replication of IBV, we utilized rapamycin as an autophagy activator and 3-methyladenine as an autophagy inhibitor. Our results indicate that IBV promotes viral replication by inducing autophagy. Further investigation revealed that IBV induces autophagosome formation by inhibiting the mTOR-ULK1 pathway and activating the activity of vacuolar protein sorting 34 (VPS34), autophagy-related gene 14, and the Beclin-1 complex. VPS34 plays a crucial role in this process, as inhibiting VPS34 protein activity enhances cell proliferation after IBV infection. Additionally, inhibiting VPS34 significantly improves the survival rate of IBV-infected chicks, suppresses IBV replication in the kidney, and alleviates tracheal, lung, and kidney damage caused by IBV infection. In summary, IBV infection can induce autophagy by modulating the mTOR/ULK1 signaling pathway and activating the VPS34 complex, while autophagy serves to promote virus replication.
    Keywords:  Autophagy; IBV; VPS34; Viral replication; mTOR/ULK1 signaling pathway
    DOI:  https://doi.org/10.1016/j.micpath.2024.106638
  4. Biochem Biophys Rep. 2024 Jul;38 101698
    Mitophagy and spermatogenesis: Role and mechanisms.
    Damilare Emmanuel Rotimi, Matthew Iyobhebhe, Elizabeth Temidayo Oluwayemi, Ikponmwosa Owen Evbuomwan, Rotdelmwa Maimako Asaleye, Oluwafemi Adeleke Ojo, Oluyomi Stephen Adeyemi.
      The mitophagy process, a type of macroautophagy, is the targeted removal of mitochondria. It is a type of autophagy exclusive to mitochondria, as the process removes defective mitochondria one by one. Mitophagy serves as an additional level of quality control by using autophagy to remove superfluous mitochondria or mitochondria that are irreparably damaged. During spermatogenesis, mitophagy can influence cell homeostasis and participates in a variety of membrane trafficking activities. Crucially, it has been demonstrated that defective mitophagy can impede spermatogenesis. Despite an increasing amount of evidence suggesting that mitophagy and mitochondrial dynamics preserve the fundamental level of cellular homeostasis, little is known about their role in developmentally controlled metabolic transitions and differentiation. It has been observed that male infertility is a result of mitophagy's impact on sperm motility. Furthermore, certain proteins related to autophagy have been shown to be present in mammalian spermatozoa. The mitochondria are the only organelle in sperm that can produce reactive oxygen species and finally provide energy for sperm movement. Furthermore, studies have shown that inhibited autophagy-infected spermatozoa had reduced motility and increased amounts of phosphorylated PINK1, TOM20, caspase 3/7, and AMPK. Therefore, in terms of reproductive physiology, mitophagy is the removal of mitochondria derived from sperm and the following preservation of mitochondria that are exclusively maternal.
    Keywords:  Autophagy; Male infertility; Reproductive health; Spermatogenesis
    DOI:  https://doi.org/10.1016/j.bbrep.2024.101698
  5. Anal Chim Acta. 2024 May 08. pii: S0003-2670(24)00307-6. [Epub ahead of print]1302 342506
    Exquisite visualization of mitophagy and monitoring the increase of lysosomal micro-viscosity in mitophagy with an unusual pH-independent lysosomal rotor.
    Rui Yang, Wei He, Changxin Zhu, Xifeng Yang, Yawei Kuang, Tao Zhu, Jingyang Xu, Yuang Zhao, Tingwang Jiang, Yushen Liu, Mengmeng Wei.
      BACKGROUND: Mitophagy plays indispensable roles in maintaining intracellular homeostasis in most eukaryotic cells by selectively eliminating superfluous components or damaged organelles. Thus, the co-operation of mitochondrial probes and lysosomal probes was presented to directly monitor mitophagy in dual colors. Nowadays, most of the lysosomal probes are composed of groups sensitive to pH, such as morpholine, amine and other weak bases. However, the pH in lysosomes would fluctuate in the process of mitophagy, leading to the optical interference. Thus, it is crucial to develop a pH-insensitive probe to overcome this tough problem to achieve exquisite visualization of mitophagy.RESULTS: In this study, we rationally prepared a pH-independent lysosome probe to reduce the optical interference in mitophagy, and thus the process of mitophagy could be directly monitored in dual color through cooperation between IVDI and MTR, depending on Förster resonance energy transfer mechanism. IVDI shows remarkable fluorescence enhancement toward the increase of viscosity, and the fluorescence barely changes when pH varies. Due to the sensitivity to viscosity, the probe can visualize micro-viscosity alterations in lysosomes without washing procedures, and it showed better imaging properties than LTR. Thanks to the inertia of IVDI to pH, IVDI can exquisitely monitor mitophagy with MTR by FRET mechanism despite the changes of lysosomal pH in mitophagy, and the reduced fluorescence intensity ratio of green and red channels can indicate the occurrence of mitophagy. Based on the properties mentioned above, the real-time increase of micro-viscosity in lysosomes during mitophagy was exquisitely monitored through employing IVDI.
    SIGNIFICANCE AND NOVELTY: Compared with the lysosomal fluorescent probes sensitive to pH, the pH-inert probe could reduce the influence of pH variation during mitophagy to achieve exquisite visualization of mitophagy in real-time. Besides, the probe could monitor the increase of lysosomal micro-viscosity in mitophagy. So, the probe possesses tremendous potential in the visualization of dynamic changes related to lysosomes in various physiological processes.
    Keywords:  Exquisitely long-term visualization; FRET mechanism; Lysosomal rotor; Mitophagy; pH-independent
    DOI:  https://doi.org/10.1016/j.aca.2024.342506
  6. J Cell Biol. 2024 Jul 01. pii: e202309057. [Epub ahead of print]223(7):
    Faa1 membrane binding drives positive feedback in autophagosome biogenesis via fatty acid activation.
    Verena Baumann, Sonja Achleitner, Susanna Tulli, Martina Schuschnig, Lara Klune, Sascha Martens.
      Autophagy serves as a stress response pathway by mediating the degradation of cellular material within lysosomes. In autophagy, this material is encapsulated in double-membrane vesicles termed autophagosomes, which form from precursors referred to as phagophores. Phagophores grow by lipid influx from the endoplasmic reticulum into Atg9-positive compartments and local lipid synthesis provides lipids for their expansion. How phagophore nucleation and expansion are coordinated with lipid synthesis is unclear. Here, we show that Faa1, an enzyme activating fatty acids, is recruited to Atg9 vesicles by directly binding to negatively charged membranes with a preference for phosphoinositides such as PI3P and PI4P. We define the membrane-binding surface of Faa1 and show that its direct interaction with the membrane is required for its recruitment to phagophores. Furthermore, the physiological localization of Faa1 is key for its efficient catalysis and promotes phagophore expansion. Our results suggest a positive feedback loop coupling phagophore nucleation and expansion to lipid synthesis.
    DOI:  https://doi.org/10.1083/jcb.202309057
  7. Trends Biochem Sci. 2024 Apr 01. pii: S0968-0004(24)00065-3. [Epub ahead of print]
    ULK/Atg1: phasing in and out of autophagy.
    Bo Wang, Gautam Pareek, Mondira Kundu.
      Autophagy - a highly regulated intracellular degradation process - is pivotal in maintaining cellular homeostasis. Liquid-liquid phase separation (LLPS) is a fundamental mechanism regulating the formation and function of membrane-less compartments. Recent research has unveiled connections between LLPS and autophagy, suggesting that phase separation events may orchestrate the spatiotemporal organization of autophagic machinery and cargo sequestration. The Unc-51-like kinase (ULK)/autophagy-related 1 (Atg1) family of proteins is best known for its regulatory role in initiating autophagy, but there is growing evidence that the functional spectrum of ULK/Atg1 extends beyond autophagy regulation. In this review, we explore the spatial and temporal regulation of the ULK/Atg1 family of kinases, focusing on their recruitment to LLPS-driven compartments, and highlighting their multifaceted functions beyond their traditional role.
    Keywords:  focal adhesion (FA); intrinsically disordered region (IDR); liquid–liquid phase separation (LLPS); pre-autophagosomal structure (PAS); stress granule (SG)
    DOI:  https://doi.org/10.1016/j.tibs.2024.03.004
  8. J Cell Physiol. 2024 Apr 03.
    Metformin protects against vascular calcification through the selective degradation of Runx2 by the p62 autophagy receptor.
      
    DOI:  https://doi.org/10.1002/jcp.31261
  9. Cell Death Discov. 2024 Apr 03. 10(1): 163
    Autophagy dysregulation via the USP20-ULK1 axis in the HERC2-related neurodevelopmental disorder.
    Joan Sala-Gaston, Eva M Pérez-Villegas, José A Armengol, Lettie E Rawlins, Emma L Baple, Andrew H Crosby, Francesc Ventura, Jose Luis Rosa.
      Sequence variants in the HERC2 gene are associated with a significant reduction in HERC2 protein levels and cause a neurodevelopmental disorder known as the HERC2-related disorder, which shares clinical features with Angelman syndrome, including global developmental delay, intellectual disability, autism, and movement disorders. Remarkably, the HERC2 gene is commonly deleted in individuals with Angelman syndrome, suggesting a potential contribution of HERC2 to the pathophysiology of this disease. Given the known critical role of autophagy in brain development and its implication in neurodevelopmental diseases, we undertook different experimental approaches to monitor autophagy in fibroblasts derived from individuals affected by the HERC2-related disorder. Our findings reveal alterations in the levels of the autophagy-related protein LC3. Furthermore, experiments with lysosomal inhibitors provide confirmation of an upregulation of the autophagy pathway in these patient-derived cells. Mechanistically, we corroborate an interaction between HERC2 and the deubiquitylating enzyme USP20; and demonstrate that HERC2 deficiency leads to increased USP20 protein levels. Notably, USP20 upregulation correlates with enhanced stability of the autophagy initiating kinase ULK1, highlighting the role of HERC2 as an autophagy regulator factor through the USP20-ULK1 axis. Moreover, we show that p38 acts as a modulator of this pathway, since p38 activation disrupts HERC2-USP20 interaction, leading to increased USP20 and LC3-II protein levels. Together, these findings uncover a previously unknown role for HERC2 in autophagy regulation and provide insights into the pathomolecular mechanisms underlying the HERC2-related disorder and Angelman syndrome.
    DOI:  https://doi.org/10.1038/s41420-024-01931-6
  10. Cell Biosci. 2024 Apr 04. 14(1): 44
    Crosstalk between m6A modification and autophagy in cancer.
    Tao Chen, Liying Zheng, Peiyue Luo, Jun Zou, Wei Li, Qi Chen, Junrong Zou, Biao Qian.
      Autophagy is a cellular self-degradation process that plays a crucial role in maintaining metabolic functions in cells and organisms. Dysfunctional autophagy has been linked to various diseases, including cancer. In cancer, dysregulated autophagy is closely associated with the development of cancer and drug resistance, and it can have both oncogenic and oncostatic effects. Research evidence supports the connection between m6A modification and human diseases, particularly cancer. Abnormalities in m6A modification are involved in the initiation and progression of cancer by regulating the expression of oncogenes and oncostatic genes. There is an interaction between m6A modification and autophagy, both of which play significant roles in cancer. However, the molecular mechanisms underlying this relationship are still unclear. m6A modification can either directly inhibit autophagy or promote its initiation, but the complex relationship between m6A modification, autophagy, and cancer remains poorly understood. Therefore, this paper aims to review the dual role of m6A and autophagy in cancer, explore the impact of m6A modification on autophagy regulation, and discuss the crucial role of the m6A modification-autophagy axis in cancer progression and treatment resistance.
    Keywords:  Autophagy; Cancer; Cancer therapy; Duality; m6A modification
    DOI:  https://doi.org/10.1186/s13578-024-01225-5
  11. Chem Biol Drug Des. 2024 Apr;103(4): e14515
    Role of autophagy and proteostasis in neurodegenerative diseases: Exploring the therapeutic interventions.
    Surbhi Panwar, Prerna Uniyal, Neelima Kukreti, Afreen Hashmi, Shivani Verma, Aanchal Arya, Gaurav Joshi.
      Neurodegenerative disorders are devastating disorders characterized by gradual loss of neurons and cognition or mobility impairment. The common pathological features of these diseases are associated with the accumulation of misfolded or aggregation of proteins. The pivotal roles of autophagy and proteostasis in maintaining cellular health and preventing the accumulation of misfolded proteins, which are associated with neurodegenerative diseases like Huntington's disease (HD), Alzheimer's disease (AD), and Parkinson's disease (PD). This article presents an in-depth examination of the interplay between autophagy and proteostasis, highlighting how these processes cooperatively contribute to cellular homeostasis and prevent pathogenic protein aggregate accumulation. Furthermore, the review emphasises the potential therapeutic implications of targeting autophagy and proteostasis to mitigate neurodegenerative diseases. While advancements in research hold promise for developing novel treatments, the article also addresses the challenges and complexities associated with modulating these intricate cellular pathways. Ultimately, advancing understanding of the underlying mechanism of autophagy and proteostasis in neurodegenerative disorders provides valuable insights into potential therapeutic avenues and future research directions.
    Keywords:  cellular homeostatis; neurodegenerative disorders; pathogenesis; proteostasis
    DOI:  https://doi.org/10.1111/cbdd.14515
  12. Mol Microbiol. 2024 Apr 04.
    LC3B labeling of the parasitophorous vacuole membrane of Plasmodium berghei liver stage parasites depends on the V-ATPase and ATG16L1.
    Annina Bindschedler, Jacqueline Schmuckli-Maurer, Sophie Buchser, Tara D Fischer, Rahel Wacker, Tim Davalan, Jessica Brunner, Volker T Heussler.
      The protozoan parasite Plasmodium, the causative agent of malaria, undergoes an obligatory stage of intra-hepatic development before initiating a blood-stage infection. Productive invasion of hepatocytes involves the formation of a parasitophorous vacuole (PV) generated by the invagination of the host cell plasma membrane. Surrounded by the PV membrane (PVM), the parasite undergoes extensive replication. During intracellular development in the hepatocyte, the parasites provoke the Plasmodium-associated autophagy-related (PAAR) response. This is characterized by a long-lasting association of the autophagy marker protein, and ATG8 family member, LC3B with the PVM. LC3B localization at the PVM does not follow the canonical autophagy pathway since upstream events specific to canonical autophagy are dispensable. Here, we describe that LC3B localization at the PVM of Plasmodium parasites requires the V-ATPase and its interaction with ATG16L1. The WD40 domain of ATG16L1 is crucial for its recruitment to the PVM. Thus, we provide new mechanistic insight into the previously described PAAR response targeting Plasmodium liver stage parasites.
    Keywords:   Plasmodium ; CASM; autophagy; host‐parasite interaction; liver stage
    DOI:  https://doi.org/10.1111/mmi.15259
  13. Curr Opin Microbiol. 2024 Mar 29. pii: S1369-5274(24)00032-8. [Epub ahead of print]79 102456
    Function of autophagy genes in innate immune defense against mucosal pathogens.
    Xiaoyan Cui, Ya-Ting Wang.
      Mucosal immunity is posed to constantly interact with commensal microbes and invading pathogens. As a fundamental cell biological pathway affecting immune response, autophagy regulates the interaction between mucosal immunity and microbes through multiple mechanisms, including direct elimination of microbes, control of inflammation, antigen presentation and lymphocyte homeostasis, and secretion of immune mediators. Some of these physiologically important functions do not involve canonical degradative autophagy but rely on certain autophagy genes and their 'autophagy gene-specific functions.' Here, we review the relationship between autophagy and important mucosal pathogens, including influenza virus, Mycobacterium tuberculosis, Salmonella enterica, Citrobacter rodentium, norovirus, and herpes simplex virus, with a particular focus on distinguishing the canonical versus gene-specific mechanisms of autophagy genes.
    DOI:  https://doi.org/10.1016/j.mib.2024.102456
  14. Biotechnol Biofuels Bioprod. 2024 Apr 02. 17(1): 50
    Regulatory mechanisms of autophagy on DHA and carotenoid accumulation in Crypthecodinium sp. SUN.
    Yiming Li, Tiantian Zhao, Weizheng Gao, Bowen Miao, Zhongxiang Fu, Zhao Zhang, Qingyang Li, Dongzhe Sun.
      BACKGROUND: Autophagy is a crucial process of cellular self-destruction and component reutilization that can affect the accumulation of total fatty acids (TFAs) and carotenoids in microalgae. The regulatory effects of autophagy process in a docosahexaenoic acid (DHA) and carotenoids simultaneously producing microalga, Crypthecodinium sp. SUN, has not been studied. Thus, the autophagy inhibitor (3-methyladenine (MA)) and activator (rapamycin) were used to regulate autophagy in Crypthecodinium sp. SUN.RESULTS: The inhibition of autophagy by 3-MA was verified by transmission electron microscopy, with fewer autophagy vacuoles observed. Besides, 3-MA reduced the glucose absorption and intracellular acetyl-CoA level, which resulting in the decrease of TFA and DHA levels by 15.83 and 26.73% respectively; Surprisingly, 3-MA increased intracellular reactive oxygen species level but decreased the carotenoids level. Comparative transcriptome analysis showed that the downregulation of the glycolysis, pentose phosphate pathway and tricarboxylic acid cycle may underlie the decrease of acetyl-CoA, NADPH and ATP supply for fatty acid biosynthesis; the downregulation of PSY and HMGCR may underlie the decreased carotenoids level. In addition, the class I PI3K-AKT signaling pathway may be crucial for the regulation of carbon and energy metabolism. At last, rapamycin was used to activate autophagy, which significantly enhanced the cell growth and TFA level and eventually resulted in 1.70-fold increase in DHA content.
    CONCLUSIONS: Our findings indicate the mechanisms of autophagy in Crypthecodinium sp. SUN and highlight a way to manipulate cell metabolism by regulating autophagy. Overall, this study provides valuable insights to guide further research on autophagy-regulated TFA and carotenoids accumulation in Crypthecodinium sp. SUN.
    Keywords:   Crypthecodinium ; Autophagy; Carotenoid; DHA; PI3K-AKT signaling pathway
    DOI:  https://doi.org/10.1186/s13068-024-02493-6
  15. Toxicology. 2024 Apr 02. pii: S0300-483X(24)00076-3. [Epub ahead of print] 153795
    mTORC1 - TFEB pathway was involved in sodium arsenite induced lysosomal alteration, oxidative stress and genetic damage in BEAS-2B cells.
    Di Ouyang, Yiren Xiong, Zuqing Hu, Jiayi He, Shanshan He, Renyi Liu, Zhenjie Gao, Dalin Hu.
      The mechanistic target of rapamycin (RAPA) complex 1 (mTORC1) - transcription factor EB (TFEB) pathway plays a crucial role in response to nutritional status, energy and environmental stress for maintaining cellular homeostasis. But there is few reports on its role in the toxic effects of arsenic exposure and the related mechanisms. Here, we show that the exposure of bronchial epithelial cells (BEAS-2B) to sodium arsenite promoted the activation of mTORC1 (p-mTORC1) and the inactivation of TFEB (p-TFEB), the number and activity of lysosomes decreased, the content of reduced glutathione (GSH) and superoxide dismutase (SOD) decreased, the content of malondialdehyde (MDA) increased, the DNA and chromosome damage elevated. Further, when mTORC1 was inhibited with RAPA, p-mTORC1 and p-TFEB down-regulated, GSH and SOD increased, MDA decreased, the DNA and chromosome damage reduced significantly, as compared with the control group. Our data revealed for the first time that mTORC1 - TFEB pathway was involved in sodium arsenite induced lysosomal alteration, oxidative stress and genetic damage in BEAS-2B cells, and it may be a potential intervention target for the toxic effects of arsenic.
    Keywords:  Sodium arsenite; genetic damage; lysosomes; mTORC1 - TFEB pathway; oxidative stress
    DOI:  https://doi.org/10.1016/j.tox.2024.153795
  16. Sci Rep. 2024 04 02. 14(1): 7707
    Neuroprotective mechanisms of luteolin in glutamate-induced oxidative stress and autophagy-mediated neuronal cell death.
    Wudtipong Vongthip, Sunita Nilkhet, Kanokkan Boonruang, Monruedee Sukprasansap, Tewin Tencomnao, Seung Joon Baek.
      Neurodegenerative diseases, characterized by progressive neuronal dysfunction and loss, pose significant health challenges. Glutamate accumulation contributes to neuronal cell death in diseases such as Alzheimer's disease. This study investigates the neuroprotective potential of Albizia lebbeck leaf extract and its major constituent, luteolin, against glutamate-induced hippocampal neuronal cell death. Glutamate-treated HT-22 cells exhibited reduced viability, altered morphology, increased ROS, and apoptosis, which were attenuated by pre-treatment with A. lebbeck extract and luteolin. Luteolin also restored mitochondrial function, decreased mitochondrial superoxide, and preserved mitochondrial morphology. Notably, we first found that luteolin inhibited the excessive process of mitophagy via the inactivation of BNIP3L/NIX and inhibited lysosomal activity. Our study suggests that glutamate-induced autophagy-mediated cell death is attenuated by luteolin via activation of mTORC1. These findings highlight the potential of A. lebbeck as a neuroprotective agent, with luteolin inhibiting glutamate-induced neurotoxicity by regulating autophagy and mitochondrial dynamics.
    Keywords:  Autophagy; Luteolin; Mitophagy; Neuroprotection; mTORC1 signaling pathway
    DOI:  https://doi.org/10.1038/s41598-024-57824-2
  17. Sci Rep. 2024 04 02. 14(1): 7739
    Identification and structural characterization of small molecule inhibitors of PINK1.
    Shafqat Rasool, Tara Shomali, Luc Truong, Nathalie Croteau, Simon Veyron, Bernardo A Bustillos, Wolfdieter Springer, Fabienne C Fiesel, Jean-François Trempe.
      Mutations in PINK1 and Parkin cause early-onset Parkinson's Disease (PD). PINK1 is a kinase which functions as a mitochondrial damage sensor and initiates mitochondrial quality control by accumulating on the damaged organelle. There, it phosphorylates ubiquitin, which in turn recruits and activates Parkin, an E3 ubiquitin ligase. Ubiquitylation of mitochondrial proteins leads to the autophagic degradation of the damaged organelle. Pharmacological modulation of PINK1 constitutes an appealing avenue to study its physiological function and develop therapeutics. In this study, we used a thermal shift assay with insect PINK1 to identify small molecules that inhibit ATP hydrolysis and ubiquitin phosphorylation. PRT062607, an SYK inhibitor, is the most potent inhibitor in our screen and inhibits both insect and human PINK1, with an IC50 in the 0.5-3 µM range in HeLa cells and dopaminergic neurons. The crystal structures of insect PINK1 bound to PRT062607 or CYC116 reveal how the compounds interact with the ATP-binding pocket. PRT062607 notably engages with the catalytic aspartate and causes a destabilization of insert-2 at the autophosphorylation dimer interface. While PRT062607 is not selective for PINK1, it provides a scaffold for the development of more selective and potent inhibitors of PINK1 that could be used as chemical probes.
    Keywords:  Inhibitor; Kinase; Mitochondria; PTEN‐induced kinase 1 (PINK1); Parkinson disease; Ubiquitin
    DOI:  https://doi.org/10.1038/s41598-024-58285-3
  18. Res Sq. 2024 Mar 19. pii: rs.3.rs-3979098. [Epub ahead of print]
    The Parkinson's disease risk gene cathepsin B promotes fibrillar alpha-synuclein clearance, lysosomal function and glucocerebrosidase activity in dopaminergic neurons.
    Jace Jones-Tabah, Kathy He, Konstantin Senkevich, Nathan Karpilovsky, Ghislaine Deyab, Yuting Cousineau, Daria Nikanorova, Taylor Goldsmith, Esther Del-Cid Pellitero, Carol Xq Chen, Wen Luo, Zhipeng You, Narges Abdian, Isabella Pietrantonio, Thomas Goiran, Jamil Ahmad, Jennifer A Ruskey, Farnaz Asayesh, Dan Spiegelman, Cheryl Waters, Oury Monchi, Yves Dauvilliers, Nicolas Dupre, Irina Miliukhina, Alla Timofeeva, Anton Emelyanov, Sofya Pchelina, Lior Greenbaum, Sharon HassinBaer, Roy N Alcalay, Austen Milnerwood, Thomas M Durcan, Ziv Gan-Or, Edward A Fon.
      Background Variants in the CTSB gene encoding the lysosomal hydrolase cathepsin B (catB) are associated with increased risk of Parkinson's disease (PD). However, neither the specific CTSB variants driving these associations nor the functional pathways that link catB to PD pathogenesis have been characterized. CatB activity contributes to lysosomal protein degradation and regulates signaling processes involved in autophagy and lysosome biogenesis. Previous in vitro studies have found that catB can cleave monomeric and fibrillar alpha-synuclein, a key protein involved in the pathogenesis of PD that accumulates in the brains of PD patients. However, truncated synuclein isoforms generated by catB cleavage have an increased propensity to aggregate. Thus, catB activity could potentially contribute to lysosomal degradation and clearance of pathogenic alpha synuclein from the cell, but also has the potential of enhancing synuclein pathology by generating aggregation-prone truncations. Therefore, the mechanisms linking catB to PD pathophysiology remain to be clarified. Methods Here, we conducted genetic analyses of the association between common and rare CTSB variants and risk of PD. We then used genetic and pharmacological approaches to manipulate catB expression and function in cell lines and induced pluripotent stem cell-derived dopaminergic neurons and assessed lysosomal activity and the handling of aggregated synuclein fibrils. Results We first identified specific non-coding variants in CTSB that drive the association with PD and are linked to changes in brain CTSB expression levels. Using iPSC-derived dopaminergic neurons we then find that catB inhibition impairs autophagy, reduces glucocerebrosidase (encoded by GBA1 ) activity, and leads to an accumulation of lysosomal content. Moreover, in cell lines, reduction of CTSB gene expression impairs the degradation of pre-formed alpha-synuclein fibrils, whereas CTSB gene activation enhances fibril clearance. Similarly, in midbrain organoids and dopaminergic neurons treated with alpha-synuclein fibrils, catB inhibition or knockout potentiates the formation of inclusions which stain positively for phosphorylated alpha-synuclein. Conclusions The results of our genetic and functional studies indicate that the reduction of catB function negatively impacts lysosomal pathways associated with PD pathogenesis, while conversely catB activation could promote the clearance of pathogenic alpha-synuclein.
    DOI:  https://doi.org/10.21203/rs.3.rs-3979098/v1
  19. Stem Cell Reports. 2024 Mar 26. pii: S2213-6711(24)00079-1. [Epub ahead of print]
    PINK1 deficiency alters muscle stem cell fate decision and muscle regenerative capacity.
    George Cairns, Madhavee Thumiah-Mootoo, Mah Rukh Abbasi, Melissa Gourlay, Jeremy Racine, Nikita Larionov, Alexandre Prola, Mireille Khacho, Yan Burelle.
      Maintenance of mitochondrial function plays a crucial role in the regulation of muscle stem cell (MuSC), but the underlying mechanisms remain ill defined. In this study, we monitored mitophagy in MuSCS under various myogenic states and examined the role of PINK1 in maintaining regenerative capacity. Results indicate that quiescent MuSCs actively express mitophagy genes and exhibit a measurable mitophagy flux and prominent mitochondrial localization to autophagolysosomes, which become rapidly decreased during activation. Genetic disruption of Pink1 in mice reduces PARKIN recruitment to mitochondria and mitophagy in quiescent MuSCs, which is accompanied by premature activation/commitment at the expense of self-renewal and progressive loss of muscle regeneration, but unhindered proliferation and differentiation capacity. Results also show that impaired fate decisions in PINK1-deficient MuSCs can be restored by scavenging excess mitochondrial ROS. These data shed light on the regulation of mitophagy in MuSCs and position PINK1 as an important regulator of their mitochondrial properties and fate decisions.
    Keywords:  fate decision; mitochondria; mitochondrial quality control; mitophagy; muscle regeneration; muscle stem cells
    DOI:  https://doi.org/10.1016/j.stemcr.2024.03.004
  20. Pharmacology. 2024 Apr 03.
    HSPA8 chaperone complex drives chaperone-mediated autophagy regulation in acute promyelocytic leukemia cell differentiation.
    Sreoshee Rafiq, Irene Mungure, Yara Banz, Nicolas J Niklaus, Thomas Kaufmann, Stefan Müller, Arnaud Jacquel, Guillaume Robert, Patrick Auberger, Bruce E Torbett, Sylviane Muller, Mario P Tschan, Magali Humbert.
      INTRODUCTION: Acute myeloid leukemia (AML) is a cancer of the hematopoietic system characterized by hyperproliferation of undifferentiated cells of the myeloid lineage. While most of AML therapies are focused towards tumor debulking, all-trans retinoic acid (ATRA) induces neutrophil differentiation in the AML subtype acute promyelocytic leukemia (APL). Macroautophagy has been extensively investigated in the context of various cancers and is often dysregulated in AML where it can have context-dependent pro- or anti-leukemogenic effects. On the contrary, the implications of chaperone-mediated autophagy (CMA) on the pathophysiology of diseases are still being explored and its role in AML has remains elusive.METHODS: We took advantages of human AML primary samples and databases to analyze CMA gene expression and activity. Furthermore, we used ATRA-sensitive (NB4) and -resistant (NB4-R1) cells to further dissect a potential function for CMA in ATRA-mediated neutrophil differentiation. NB4-R1 cells are unique in that they do respond to retinoic acid transcriptionally, but do not mature in response to retinoid signaling alone unless maturation is triggered by adding cAMP.
    RESULTS: Here, we report that CMA related mRNA transcripts are significantly higher expressed in immature hematopoietic cells as compared to neutrophils, contrasting the macroautophagy gene expression patterns. Accordingly, lysosomal degradation of an mCherry-KFERQ CMA reporter decreases during ATRA-induced differentiation of APL cells. On the other hand, using NB4-R1 cells we found that macroautophagy flux primed ATRA resistant NB4-R1 cells to differentiate upon ATRA treatment, but reduced association of lysosome-associated membrane protein type 2A (LAMP-2A) and heat shock protein family A (Hsp70) member 8 (HSPA8), which are necessary for complete neutrophil maturation. Accordingly, depletion of HSPA8 attenuated CMA activity and facilitated APL cell differentiation. In contrast, maintaining high CMA activity by ectopic expression of LAMP-2A impeded APL differentiation.
    CONCLUSION: Overall, our findings suggest that APL neutrophil differentiation requires CMA inactivation and that this pathway predominantly depends on HSPA8 and is possibly assisted by other co-chaperones.
    DOI:  https://doi.org/10.1159/000537864
  21. Sci Rep. 2024 Apr 03. 14(1): 7877
    Chronic replication stress invokes mitochondria dysfunction via impaired parkin activity.
    Tsuyoshi Kawabata, Reiko Sekiya, Shinji Goto, Tao-Sheng Li.
      Replication stress is a major contributor to tumorigenesis because it provides a source of chromosomal rearrangements via recombination events. PARK2, which encodes parkin, a regulator of mitochondrial homeostasis, is located on one of the common fragile sites that are prone to rearrangement by replication stress, indicating that replication stress may potentially impact mitochondrial homeostasis. Here, we show that chronic low-dose replication stress causes a fixed reduction in parkin expression, which is associated with mitochondrial dysfunction, indicated by an increase in mtROS. Consistent with the major role of parkin in mitophagy, reduction in parkin protein expression was associated with a slight decrease in mitophagy and changes in mitochondrial morphology. In contrast, cells expressing ectopic PARK2 gene does not show mtROS increases and changes in mitochondrial morphology even after exposure to chronic replication stress, suggesting that intrinsic fragility at PARK2 loci associated with parkin reduction is responsible for mitochondrial dysfunction caused by chronic replication stress. As endogenous replication stress and mitochondrial dysfunction are both involved in multiple pathophysiology, our data support the therapeutic development of recovery of parkin expression in human healthcare.
    DOI:  https://doi.org/10.1038/s41598-024-58656-w
  22. J Cell Sci. 2024 Apr 05. pii: jcs.261765. [Epub ahead of print]
    Collapse of late endosomal pH elicits a rapid Rab7 response via V-ATPase and RILP.
    R J Mulligan, M M Magaj, L Digilio, S Redemann, C C Yap, B Winckler.
      Endosomal-lysosomal trafficking is accompanied by the acidification of endosomal compartments by the H+-V-ATPase to reach low lysosomal pH. Disruption of proper pH impairs lysosomal function and the balance of protein synthesis and degradation (proteostasis). We used the small dipeptide LLOMe, which is known to permeabilize lysosomal membranes, and find that LLOMe also impacts late endosomes (LEs) by neutralizing their pH without causing membrane permeabilization. We show that LLOMe leads to hyper-activation of Rab7 and disruption of tubulation and mannose-6-phosphate receptor (CI-M6PR) recycling on pH-neutralized LEs. Either pH neutralization (NH4Cl) or Rab7 hyper-active mutants alone can phenocopy the alterations in tubulation and CI-M6PR trafficking. Mechanistically, pH neutralization increases the assembly of the V1G1 subunit of the V-ATPase on endosomal membranes, which stabilizes GTP-bound Rab7 via RILP, a known interactor of Rab7 and V1G1. We propose a novel pathway by which V-ATPase and RILP modulate LE pH and Rab7 activation in concert. This pathway might broadly contribute to pH control during physiologic endosomal maturation or starvation and during pathologic pH neutralization, which occurs via lysosomotropic compounds or in disease states.
    Keywords:  Acidification; Late endosome; Lysosomal membrane permeabilization; Membrane trafficking; RILP; Rab7; V-ATPase
    DOI:  https://doi.org/10.1242/jcs.261765
  23. Cancer Lett. 2024 Apr 03. pii: S0304-3835(24)00236-2. [Epub ahead of print] 216843
    Recent advancement of autophagy in polyploid giant cancer cells and its interconnection with senescence and stemness for therapeutic opportunities.
    Srimanta Patra, Prajna Paramita Naik, Kewal Kumar Mahapatra, Moureq Rashed Alotaibi, Shankargouda Patil, Birija Sankar Patro, Gautam Sethi, Thomas Efferth, Sujit Kumar Bhutia.
      Recurrent chemotherapy-induced senescence and resistance are attributed to the polyploidization of cancer cells that involves genomic instability and poor prognosis due to their unique form of cellular plasticity. Autophagy, a pre-dominant cell survival mechanism, is crucial during carcinogenesis and chemotherapeutic stress, favouring polyploidization. The selective autophagic degradation of essential proteins associated with several cell cycle progression checkpoints deregulates mitosis fidelity and genomic integrity, imparting polyploidization of cancer cells. In connection with cytokinesis failure and endoreduplication, autophagy promotes the formation, maintenance, and generation of the progeny of polyploid giant cancer cells. The polyploid cancer cells embark on autophagy-guarded elevation in the expression of stem cell markers, along with triggered epithelial and mesenchymal transition and senescence. The senescent polyploid escapers represent a high autophagic index than the polyploid progeny, suggesting regaining autophagy induction and subsequent autophagic degradation, which is essential for escaping from senescence/polyploidy, leading to a higher proliferative phenotypic progeny. This review documents the various causes of polyploidy and its consequences in cancer with relevance to autophagy modulation and its targeting for therapeutic intervention as a novel therapeutic strategy for personalized and precision medicine.
    Keywords:  Autophagy; Cancer; Polyploidy; Senescence; Stemness
    DOI:  https://doi.org/10.1016/j.canlet.2024.216843
  24. bioRxiv. 2024 Mar 13. pii: 2024.03.08.584091. [Epub ahead of print]
    Epigenetic Reprogramming of Autophagy Drives Mutant IDH1 Glioma Progression and Response to Radiation.
    Felipe J Núñez, Kaushik Banerjee, Anzar A Mujeeb, Ava Mauser, Claire E Tronrud, Ziwen Zhu, Ayman Taher, Padma Kadiyala, Stephen V Carney, Maria B Garcia-Fabiani, Andrea Comba, Mahmoud S Alghamri, Brandon L McClellan, Syed M Faisal, Zeribe C Nwosu, Hanna S Hong, Tingting Qin, Maureen A Sartor, Mats Ljungman, Shi-Yuan Cheng, Henry D Appelman, Pedro R Lowenstein, Joerg Lahann, Costas A Lyssiotis, Maria G Castro.
      Mutant isocitrate dehydrogenase 1 (mIDH1; IDH1 R132H ) exhibits a gain of function mutation enabling 2-hydroxyglutarate (2HG) production. 2HG inhibits DNA and histone demethylases, inducing epigenetic reprogramming and corresponding changes to the transcriptome. We previously demonstrated 2HG-mediated epigenetic reprogramming enhances DNA-damage response and confers radioresistance in mIDH1 gliomas harboring p53 and ATRX loss of function mutations. In this study, RNA-seq and ChIP-seq data revealed human and mouse mIDH1 glioma neurospheres have downregulated gene ontologies related to mitochondrial metabolism and upregulated autophagy. Further analysis revealed that the decreased mitochondrial metabolism was paralleled by a decrease in glycolysis, rendering autophagy as a source of energy in mIDH1 glioma cells. Analysis of autophagy pathways showed that mIDH1 glioma cells exhibited increased expression of pULK1-S555 and enhanced LC3 I/II conversion, indicating augmented autophagy activity. This dependence is reflected by increased sensitivity of mIDH1 glioma cells to autophagy inhibition. Blocking autophagy selectively impairs the growth of cultured mIDH1 glioma cells but not wild-type IDH1 (wtIDH1) glioma cells. Targeting autophagy by systemic administration of synthetic protein nanoparticles packaged with siRNA targeting Atg7 (SPNP-siRNA-Atg7) sensitized mIDH1 glioma cells to radiation-induced cell death, resulting in tumor regression, long-term survival, and immunological memory, when used in combination with IR. Our results indicate autophagy as a critical pathway for survival and maintenance of mIDH1 glioma cells, a strategy that has significant potential for future clinical translation.One Sentence Summary: The inhibition of autophagy sensitizes mIDH1 glioma cells to radiation, thus creating a promising therapeutic strategy for mIDH1 glioma patients.
    Graphical abstract: Our genetically engineered mIDH1 mouse glioma model harbors IDH1 R132H in the context of ATRX and TP53 knockdown. The production of 2-HG elicited an epigenetic reprogramming associated with a disruption in mitochondrial activity and an enhancement of autophagy in mIDH1 glioma cells. Autophagy is a mechanism involved in cell homeostasis related with cell survival under energetic stress and DNA damage protection. Autophagy has been associated with radio resistance. The inhibition of autophagy thus radio sensitizes mIDH1 glioma cells and enhances survival of mIDH1 glioma-bearing mice, representing a novel therapeutic target for this glioma subtype with potential applicability in combined clinical strategies.
    DOI:  https://doi.org/10.1101/2024.03.08.584091
  25. J Invest Dermatol. 2024 Apr 01. pii: S0022-202X(24)00185-4. [Epub ahead of print]
    Autophagy Modulation in Endothelial Hyperglycemia-Induced Wound-Healing Impairment.
    Daniele Bergamaschi.
      
    DOI:  https://doi.org/10.1016/j.jid.2024.03.005
  26. Autophagy. 2024 Apr 02.
    ATF6 supports lysosomal function in tumor cells to enable ER stress-activated macroautophagy and CMA: impact on mutant TP53 expression.
    Rossella Benedetti, Maria Anele Romeo, Andrea Arena, Maria Saveria Gilardini Montani, Gabriella D'Orazi, Mara Cirone.
      The inhibition of the unfolded protein response (UPR), which usually protects cancer cells from stress, may be exploited to potentiate the cytotoxic effect of drugs inducing ER stress. However, in this study, we found that ER stress and UPR activation by thapsigargin or tunicamycin promoted the lysosomal degradation of mutant (MUT) TP53 and that the inhibition of the UPR sensor ATF6, but not of ERN1/IRE1 or EIF2AK3/PERK, counteracted such an effect. ATF6 activation was indeed required to sustain the function of lysosomes, enabling the execution of chaperone-mediated autophagy (CMA) as well as of macroautophagy, processes involved in the degradation of MUT TP53 in stressed cancer cells. At the molecular level, by pharmacological and genetic approaches, we demonstrated that the inhibition of ATF6 correlated with the activation of MTOR and with TFEB and LAMP1 downregulation in thapsigargin-treated MUT TP53 carrying cells. We hypothesize that the rescue of MUT TP53 expression by ATF6 inhibition, could further activate MTOR and maintain lysosomal dysfunction, further inhibiting MUT TP53 degradation, in a vicious circle. The findings of this study suggest that the presence of MUT TP53, which often exerts oncogenic properties, should be considered before approaching treatments combining ER stressors with ATF6 inhibitors against cancer cells, while it could represent a promising strategy against cancer cells that harbor WT TP53.
    Keywords:  ATF6; CMA; Mutant TP53; UPR; cathepsins; thapsigargin
    DOI:  https://doi.org/10.1080/15548627.2024.2338577
  27. Inflammopharmacology. 2024 Apr 02.
    Autophagy and exosomes; inter-connected maestros in Alzheimer's disease.
    Hanaa B Atya, Nadia Mohamed Sharaf, Ragwa Mansour Abdelghany, Sara Nageeb El-Helaly, Heba Taha.
      Autophagy is a crucial process involved in the degradation and recycling of cytoplasmic components which are transported to the lysosomal compartment by autophagosomes. Exosomes are an important means of communication and signaling in both normal and diseased states, and they have a significant role in the transmission and propagation of proteins, especially proteins implicated in neurodegenerative disorders. Autophagy may affect exosomal processing, but whether autophagy controls the release of aggregated β-amyloid and tau proteins in exosomes of Alzheimer disease (AD) is unclear. Therefore, our study aimed to investigate how modulating autophagy affects the exosomal release of these proteins in animal models of AD. Isolated exosomes from brain tissues of 48 male albino mice were divided into four groups (Negative control, LPS, rapamycin (RAPA), and chloroquine (CQ). LC3 I and LC3 II as well as Aβ and Tau proteins levels were determined. All mice undergone Neuro-behavioral tests (Morris Water maze test, Y-maze test, and Novel Object Recognition). Both LPS and CQ groups showed reduced expression levels of LC3 II and LC3 II/LC3 I ratio. In contrast, RAPA group showed a significant increase in both LC3-II expression and LC3-II/LC3-I ratio. The levels of both Aβ & Tau in exosomes of CQ & LPS groups were higher. While RAPA group showed a significant diminished levels of tau & Aβ proteins. In conclusion, our findings suggest that autophagy alterations in AD can influence the release of Aβ and tau proteins through exosomes, which may impact the spread of misfolded proteins in AD. These results highlight a potential innovative therapeutic approach for combating AD.
    Keywords:  Alzheimer disease (AD); Autophagy; Exosomes
    DOI:  https://doi.org/10.1007/s10787-024-01466-3
  28. bioRxiv. 2024 Mar 21. pii: 2024.03.21.586175. [Epub ahead of print]
    PLD3 and PLD4 synthesize S,S -BMP, a key phospholipid enabling lipid degradation in lysosomes.
    Shubham Singh, Ulrich Dransfeld, Yohannes Ambaw, Joshua Lopez-Scarim, Robert V Farese, Tobias C Walther.
      Bis(monoacylglycero)phosphate (BMP) is an abundant lysosomal phospholipid required for degradation of lipids, in particular gangliosides. Alterations in BMP levels are associated with neurodegenerative diseases. Unlike typical glycerophospholipids, lysosomal BMP has two chiral glycerol carbons in the S (rather than the R ) stereo-conformation, protecting it from lysosomal degradation. How this unusual and yet crucial S,S- stereochemistry is achieved is unknown. Here we report that phospholipases D3 and D4 (PLD3 and PLD4) synthesize lysosomal S,S- BMP, with either enzyme catalyzing the critical glycerol stereo-inversion reaction in vitro . Deletion of PLD3 or PLD4 markedly reduced BMP levels in cells or in murine tissues where either enzyme is highly expressed (brain for PLD3; spleen for PLD4), leading to gangliosidosis and lysosomal abnormalities. PLD3 mutants associated with neurodegenerative diseases, including Alzheimer's disease risk, diminished PLD3 catalytic activity. We conclude that PLD3/4 enzymes synthesize lysosomal S,S- BMP, a crucial lipid for maintaining brain health.
    DOI:  https://doi.org/10.1101/2024.03.21.586175
  29. FASEB J. 2024 Apr 15. 38(7): e23562
    Proximal tubular MBD2 promotes autophagy to drive the progression of AKI caused by vancomycin via regulation of miR-597-5p/S1PR1 axis.
    Yong Guo, Dengke Wu, Xiaozhou Li, Juan Wang, Huiling Li, Yijian Li, Dan Luo, Feng Yi, Dongshan Zhang.
      Our recent investigation has indicated that the global deletion of MBD2 can mitigate the progression of AKI induced by VAN. Nevertheless, the role and regulatory mechanisms of proximal tubular MBD2 in this pathophysiological process have yet to be elucidated. Our preceding investigation revealed that autophagy played a crucial role in advancing AKI induced by VAN. Consequently, we postulated that MBD2 present in the proximal tubule could upregulate the autophagic process to expedite the onset of AKI. In the present study, we found for the first time that MBD2 mediated the autophagy production induced by VAN. Through the utilization of miRNA chip analysis, we have mechanistically demonstrated that MBD2 initiates the activation of miR-597-5p through promoter demethylation. This process leads to the suppression of S1PR1, which results in the induction of autophagy and apoptosis in renal tubular cells. Besides, PT-MBD2-KO reduced autophagy to attenuate VAN-induced AKI via regulation of the miR-597-5p/S1PR1 axis, which was reversed by rapamycin. Finally, the overexpression of MBD2 aggravated the diminished VAN-induced AKI in autophagy-deficient mice (PT-Atg7-KO). These data demonstrate that proximal tubular MBD2 facilitated the process of autophagy via the miR-597-5p/S1PR1 axis and subsequently instigated VAN-induced AKI through the induction of apoptosis. The potentiality of MBD2 being a target for AKI was established.
    Keywords:  AKI; MBD2; SPIR1; autophagy; miR‐597‐5p
    DOI:  https://doi.org/10.1096/fj.202301500R
  30. Autophagy. 2024 Apr 02.
    LC3B conjugation machinery promotes autophagy-independent HIV-1 entry in CD4+ T lymphocytes.
    Baptiste Pradel, Guilhem Cantaloube, Marie Villares, Maïka S Deffieu, Véronique Robert-Hebmann, Vincent Lucansky, Mathias Faure, Nathalie Chazal, Raphaël Gaudin, Lucile Espert.
      HIV-1 entry into CD4+ T lymphocytes relies on the viral and cellular membranes' fusion, leading to viral capsid delivery in the target cell cytoplasm. Atg8/LC3B conjugation to lipids, process named Atg8ylation mainly studied in the context of macroautophagy/autophagy, occurs transiently in the early stages of HIV-1 replication in CD4+ T lymphocytes. Despite numerous studies investigating the HIV-1-autophagy interplays, the Atg8ylation impact in these early stages of infection remains unknown. Here we found that HIV-1 exposure leads to the rapid LC3B enrichment toward the target cell plasma membrane, in close proximity with the incoming viral particles. Furthermore, we demonstrated that Atg8ylation is a key event facilitating HIV-1 entry in target CD4+ T cells. Interestingly, this effect is independent of canonical autophagy as ATG13 silencing does not prevent HIV-1 entry. Together, our results provide an unconventional role of LC3B conjugation subverted by HIV-1 to achieve a critical step of its replication cycle.
    Keywords:  Atg8ylation; CD4+ T lymphocyte; HIV-1; LC3B; virus entry
    DOI:  https://doi.org/10.1080/15548627.2024.2338573
  31. NanoImpact. 2024 Apr 03. pii: S2452-0748(24)00015-6. [Epub ahead of print] 100505
    Low-dose cadmium telluride quantum dots trigger M1 polarization in macrophages through mTOR-mediated transcription factor EB activation.
    Tingting Wei, Na Liu, Yongshuai Yao, Xiaoquan Huang, Zhihui Wang, Tianshu Wu, Ting Zhang, Yuying Xue, Meng Tang.
      The increasing application of quantum dots (QDs) increases interactions with organisms. The inflammatory imbalance is a significant manifestation of immunotoxicity. Macrophages maintain inflammatory homeostasis. Using macrophages differentiated by phorbol 12-myristate 13-acetate-induced THP-1 cells as models, the study found that low-dose (5 μM) cadmium telluride QDs (CdTe-QDs) hindered monocyte-macrophage differentiation. CD11b is a surface marker of macrophage, and the addition of CdTe-QDs during induction resulted in a decrease in CD11b expression. Moreover, exposure of differentiated THP-1 macrophage (dTHP-1) to 5 μM CdTe-QDs led to the initiation of M1 polarization. This was indicated by the increased surface marker CD86 expression, along with elevated level of NF-κB and IL-1β proteins. The potential mechanisms are being explored. The transcription factor EB (TFEB) plays a significant role in immune regulation and serves as a crucial regulator of the autophagic lysosomal pathway. After exposed to CdTe-QDs, TFEB activation-mediated autophagy and M1 polarization were observed to occur simultaneously in dTHP-1. The mTOR signaling pathway contributed to TFEB activation induced by CdTe-QDs. However, mTOR-independent activation of TFEB failed to promote M1 polarization. These results suggest that mTOR-TFEB is an advantageous target to enhance the biocompatibility of CdTe-QDs.
    Keywords:  Autophagy; Immunoregulation; Inflammation; Quantum dots
    DOI:  https://doi.org/10.1016/j.impact.2024.100505
  32. Autophagy. 2024 Apr 02.
    The matrix protein of lyssavirus hijacks autophagosome for efficient egress by recruiting NEDD4 through its PPxY motif.
    Yueming Yuan, An Fang, Zhihui Wang, Huanchun Chen, Zhen F Fu, Ming Zhou, Ling Zhao.
      Lyssaviruses are well-known worldwide and often cause fatal encephalitis. Previous studies have shown that autophagy is beneficial for the replication of rabies virus (RABV), the representative lyssavirus, but the detailed mechanism remains obscure. In this study, we showed that the rabies virus matrix protein (RABV-M) used its PPxY motif to interact with the E3 ubiquitin-protein ligase NEDD4. NEDD4 then recruited MAP1LC3/LC3 via its LC3-interacting region (LIR). Interestingly, after binding to the ubiquitinated RABV-M, NEDD4 could bind more LC3 and enhance autophagosome accumulation, while NEDD4 knockdown significantly reduced M-induced autophagosome accumulation. Further study revealed that RABV-M prevented autophagosome-lysosome fusion and facilitated viral budding. Inhibition of RABV-M-induced autophagosome accumulation reduced the production of extracellular virus-like particles. We also found that M proteins of most lyssaviruses share the same mechanism to accumulate autophagosome by hijacking NEDD4. Collectively, this study revealed a novel strategy for lyssaviruses to achieve efficient viral replication by exploiting the host autophagy system.
    Keywords:  Autophagosome; Neural precursor cell-expressed developmentally down-regulated 4 (NEDD4); Rabies virus (RABV); Virus-like particle (VLP); lyssavirus; matrix protein; viral budding
    DOI:  https://doi.org/10.1080/15548627.2024.2338575
  33. ACS Infect Dis. 2024 Apr 01.
    Role of Macrophage PIST Protein in Regulating Leishmania major Infection.
    Sourav Banerjee, Mandip Pratham Gadpayle, Suman Samanta, Priyanka Dutta, Swagata Das, Rupak Datta, Sankar Maiti.
      PDZ protein interacting specifically with Tc10 or PIST is a mammalian trans-Golgi resident protein that regulates subcellular sorting of plasma membrane receptors. PIST has recently emerged as a key player in regulating viral pathogenesis. Nevertheless, the involvement of PIST in parasitic infections remains unexplored. Leishmania parasites infiltrate their host macrophage cells through phagocytosis, where they subsequently multiply within the parasitophorous vacuole (PV). Host cell autophagy has been found to be important in regulating this parasite infection. Since PIST plays a pivotal role in triggering autophagy through the Beclin 1-PI3KC3 pathway, it becomes interesting to identify the status of PIST during Leishmania infection. We found that while macrophage cells are infected with Leishmania major (L. major), the expression of PIST protein remains unaltered; however, it traffics from the Golgi compartment to PV. Further, we identified that in L. major-infected macrophage cells, PIST associates with the autophagy regulatory protein Beclin 1 within the PVs; however, PIST does not interact with LC3. Reduction in PIST protein through siRNA silencing significantly increased parasite burden, whereas overexpression of PIST in macrophages restricted L. major infectivity. Together, our study reports that the macrophage PIST protein is essential in regulating L. major infectivity.
    Keywords:  Beclin 1; Golgi; Leishmania; PIST; macrophage
    DOI:  https://doi.org/10.1021/acsinfecdis.4c00156
  34. J Cereb Blood Flow Metab. 2024 Apr 04. 271678X241245557
    RNF213 variant and autophagic impairment: A pivotal link to endothelial dysfunction in moyamoya disease.
    Hee Sun Shin, Geun Hwa Park, Eun Sil Choi, So Young Park, Da Sol Kim, Jaerak Chang, Ji Man Hong.
      Moyamoya disease (MMD) is closely associated with the Ring Finger Protein 213 (RNF213), a susceptibility gene for MMD. However, its biological function remains unclear. We aimed to elucidate the role of RNF213 in the damage incurred by human endothelial cells under oxygen-glucose deprivation (OGD). We analyzed autophagy in peripheral blood mononuclear cells (PBMCs) derived from patients carrying either RNF213 wildtype (WT) or variant (p.R4810K). Subsequently, human umbilical vein endothelial cells (HUVECs) were transfected with RNF213 WT (HUVECWT) or p.R4810K (HUVECR4810K) and exposed to OGD for 2 h. Immunoblotting was used to analyze autophagy marker proteins, and endothelial function was analyzed by tube formation assay. Autophagic vesicles were observed using transmission electron microscopy. Post-OGD exposure, we administered rapamycin and cilostazol as potential autophagy inducers. The RNF213 variant group during post-OGD exposure (vs. pre-OGD) showed autophagy inhibition, increased protein expression of SQSTM1/p62 (p < 0.0001) and LC3-II (p = 0.0039), and impaired endothelial function (p = 0.0252). HUVECR4810K during post-OGD exposure (versus pre-OGD) showed a remarkable increase in autophagic vesicles. Administration of rapamycin and cilostazol notably restored the function of HUVECR4810K and autophagy. Our findings support the pivotal role of autophagy impaired by the RNF213 variant in MMD-induced endothelial cell dysfunction.
    Keywords:  Autophagy; RNF213; cilostazol; endothelial dysfunction; moyamoya disease
    DOI:  https://doi.org/10.1177/0271678X241245557
  35. Free Radic Biol Med. 2024 Apr 01. pii: S0891-5849(24)00163-1. [Epub ahead of print]
    Mapping the interplay of immunoproteasome and autophagy in different heart failure phenotypes.
    Christiane Ott.
      Proper protein degradation is required for cellular protein homeostasis and organ function. Particularly, in post-mitotic cells, such as cardiomyocytes, unbalanced proteolysis due to inflammatory stimuli and oxidative stress contributes to organ dysfunction. To ensure appropriate protein turnover, eukaryotic cells exert two main degradation systems, the ubiquitin-proteasome-system and the autophagy-lysosome-pathway. It has been shown that proteasome activity affects the development of cardiac dysfunction differently, depending on the type of heart failure. Studies analyzing the inducible subtype of the proteasome, the immunoproteasome (i20S), demonstrated that the i20S plays a double role in diseased hearts. While i20S subunits are increased in cardiac hypertrophy, atrial fibrillation and partly in myocarditis, the opposite applies to diabetic cardiomyopathy and ischemia/reperfusion injury. In addition, the i20S appears to play a role in autophagy modulation depending on heart failure phenotype. This review summarizes the current literature on the i20S in different heart failure phenotypes, emphasizing the two faces of i20S in injured hearts. A selection of established i20S inhibitors is introduced and signaling pathways linking the i20S to autophagy are highlighted. Mapping the interplay of the i20S and autophagy in different types of heart failure offers potential approaches for developing treatment strategies against heart failure.
    Keywords:  11S; Cardiac injury; Crosstalk; Hypertrophy; Immunoproteasome
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2024.03.026
  36. Trends Endocrinol Metab. 2024 Feb;pii: S1043-2760(23)00214-X. [Epub ahead of print]35(2): 125-141
    Common and divergent molecular mechanisms of fasting and ketogenic diets.
    Antonio Paoli, Grant M Tinsley, Mark P Mattson, Immaculata De Vivo, Ravi Dhawan, Tatiana Moro.
      Intermittent short-term fasting (ISTF) and ketogenic diets (KDs) exert overlapping but not identical effects on cell metabolism, function, and resilience. Whereas health benefits of KD are largely mediated by the ketone bodies (KBs), ISTF engages additional adaptive physiological responses. KDs act mainly through inhibition of histone deacetylases (HDACs), reduction of oxidative stress, improvement of mitochondria efficiency, and control of inflammation. Mechanisms of action of ISTF include stimulation of autophagy, increased insulin and leptin sensitivity, activation of AMP-activated protein kinase (AMPK), inhibition of the mechanistic target of rapamycin (mTOR) pathway, bolstering mitochondrial resilience, and suppression of oxidative stress and inflammation. Frequent switching between ketogenic and nonketogenic states may optimize health by increasing stress resistance, while also enhancing cell plasticity and functionality.
    Keywords:  brain; fasting; ketogenic diet; ketone bodies; mitochondria; time-restricted eating
    DOI:  https://doi.org/10.1016/j.tem.2023.10.001
  37. Free Radic Biol Med. 2024 Apr 02. pii: S0891-5849(24)00167-9. [Epub ahead of print]
    Targeting NKAα1 to treat Parkinson's disease through inhibition of mitophagy-dependent ferroptosis.
    Xiaoyan Zhang, Guanghong Li, Hanbin Chen, Xiao-Wei Nie, Jin-Song Bian.
      Dysfunction of the Na+/K+-ATPase (NKA) has been documented in various neurodegenerative diseases, yet the specific role of NKAα1 in Parkinson's disease (PD) remains incompletely understood. In this investigation, we utilized NKAα1 haploinsufficiency (NKAα1+/-) mice to probe the influence of NKAα1 on dopaminergic (DA) neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our findings reveal that NKAα1+/- mice displayed a heightened loss of DA neurons and more pronounced motor dysfunction compared to the control group when exposed to MPTP. Intriguingly, this phenomenon coincided with the activation of ferroptosis and impaired mitophagy both in vivo and in vitro. To scrutinize the role and underlying mechanism of NKAα1 in PD, we employed DR-Ab, an antibody targeting the DR-region of the NKA α subunit. Our study demonstrates that the administration of DR-Ab effectively reinstated the membrane abundance of NKAa1, thereby mitigating MPTP-induced DA neuron loss and subsequent improvement in behavioral deficit. Mechanistically, DR-Ab heightened the formation of the surface NKAα1/SLC7A11 complex, inhibiting SLC7A11-dependent ferroptosis. Moreover, DR-Ab disrupted the cytosolic interaction between NKAα1 and Parkin, facilitating the translocation of Parkin to mitochondria and enhancing the process of mitophagy. In conclusion, this study establishes NKAα1 as a key regulator of ferroptosis and mitophagy, identifying its DR-region as a promising therapeutic target for PD.
    Keywords:  DR-Ab; Ferroptosis; Mitophagy; Na(+)/K(+) ATPase; Parkinson's disease
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2024.04.002
  38. bioRxiv. 2024 Mar 20. pii: 2024.03.19.585812. [Epub ahead of print]
    The autophagy protein, ATG14 safeguards against unscheduled pyroptosis activation to enable embryo transport during early pregnancy.
    Pooja Popli, Arin K Oestreich, Vineet K Maurya, Marina N Rowen, Ramya Masand, Michael J Holtzman, Yong Zhang, John Lydon, Shizuo Akira, Kelle H Moley, Ramakrishna Kommagani.
      Recurrent pregnancy loss (RPL), characterized by two or more failed clinical pregnancies, poses a significant challenge to reproductive health. In addition to embryo quality and endometrial function, proper oviduct function is also essential for successful pregnancy establishment. Therefore, structural abnormalities or inflammation resulting from infection in the oviduct may impede the transport of embryos to the endometrium, thereby increasing the risk of miscarriage. However, the precise cellular mechanisms that maintain the structural and functional integrity of the oviduct are not studied yet. Here, we report that autophagy is critical for maintaining the oviduct homeostasis and keeping the inflammation under check to enable embryo transport. Specifically, the loss of the autophagy-related gene, Atg14 in the oviduct causes severe structural abnormalities compromising its cellular plasticity and integrity leading to the retention of embryos. Interestingly, the selective loss of Atg14 in oviduct ciliary epithelial cells did not impact female fertility, highlighting the specificity of ATG14 function in distinct cell types within the oviduct. Mechanistically, loss of Atg14 triggered unscheduled pyroptosis leading to inappropriate embryo retention and impeded embryo transport in the oviduct. Finally, pharmacological activation of pyroptosis in pregnant mice led to an impairment in embryo transport. Together, we found that ATG14 safeguards against unscheduled pyroptosis activation to enable embryo transport from the oviduct to uterus for the successful implantation. Of clinical significance, these findings provide possible insights on the underlying mechanism(s) of early pregnancy loss and might aid in developing novel prevention strategies using autophagy modulators.
    DOI:  https://doi.org/10.1101/2024.03.19.585812
  39. Chem Biol Interact. 2024 Apr 03. pii: S0009-2797(24)00136-4. [Epub ahead of print] 110990
    Autophagic-lysosomal damage induced by swainsonine is protected by trehalose through activation of TFEB-regulated pathway in renal tubular epithelial cells.
    Shuhang Zhang, Hai Yin, Yiqingqing Zhang, Yanli Zhu, Xueyao Zhu, Wenting Zhu, Lihui Tang, Yiling Liu, Kexin Wu, Baoyu Zhao, Yanan Tian, Hao Lu.
      Swainsonine (SW) is the main toxic component of locoweed. Previous studies have shown that kidney damage is an early pathologic change in locoweed poisoning in animals. Trehalose induces autophagy and alleviates lysosomal damage, while its protective effect and mechanism against the toxic injury induced by SW is not clear. Based on the published literature, we hypothesize that transcription factor EB(TFEB) -regulated is targeted by SW and activating TFEB by trehalose would reverse the toxic effects. In this study, we investigate the mechanism of protective effects of trehalose using renal tubular epithelial cells. The results showed that SW induced an increase in the expression level of microtubule-associated protein light chain 3-II and p62 proteins and a decrease in the expression level of ATPase H+ transporting V1 Subunit A, Cathepsin B, Cathepsin D, lysosome-associated membrane protein 2 and TFEB proteins in renal tubular epithelial cells in a time and dose-dependent manner suggesting TFEB-regulated lysosomal pathway is adversely affected by SW. Conversely, treatment with trehalose, a known activator of TFEB promote TFEB nuclear translocation suggesting that TFEB plays an important role in protection against SW toxicity. We demonstrated in lysosome staining that SW reduced the number of lysosomes and increased the luminal pH, while trehalose could counteract these SW-induced effects. In summary, our results demonstrated for the first time that trehalose could alleviate the autophagy degradation disorder and lysosomal damage induced by SW. Our results provide an interesting method for reversion of SW-induced toxicity in farm animals and furthermore, activation of TFEB by trehalose suggesting novel mechanism of treating lysosomal storage diseases.
    Keywords:  Autophagy; Lysosome damage; Renal tubular epithelial cells; Swainsonine; Trehalose
    DOI:  https://doi.org/10.1016/j.cbi.2024.110990
  40. Phytother Res. 2024 Apr 01.
    Fraxetin pretreatment alleviates cisplatin-induced kidney injury by antagonizing autophagy and apoptosis via mTORC1 activation.
    Ziwei Yuan, Xuejia Yang, Zujian Hu, Yuanyuan Gao, Mengsi Wang, Lili Xie, Hengyue Zhu, Chaosheng Chen, Hong Lu, Yongheng Bai.
      Cisplatin-induced kidney injury (CKI) is a common complication of chemotherapy. Fraxetin, derived from Fraxinus bungeana A. DC. bark, has antioxidant, anti-inflammatory, and anti-fibrotic effects. This study aims to investigate fraxetin's effects on CKI and its underlying mechanism in vivo and in vitro. Tubular epithelial cells (TECs) and mice were exposed to cisplatin with and without fraxetin preconditioning assess fraxetin's role in CKI. TECs autophagy was observed using transmission electron microscopy. Apoptosis levels in animal tissues were measured using TUNEL staining. The protective mechanism of fraxetin was explored through pharmacological and genetic regulation of mTORC1. Molecular docking was used to identify potential binding sites between fraxetin and mTORC1. The results indicated that fraxetin pretreatment reduced cisplatin-induced kidney injury in a time- and concentration-dependent way. Fraxetin also decreased autophagy in TECs, as observed through electron microscopy. Tissue staining confirmed that fraxetin pretreatment significantly reduced cisplatin-induced apoptosis. Inhibition of mTORC1 using rapamycin or siRNA reversed the protective effects of fraxetin on apoptosis and autophagy in cisplatin-treated TECs, while activation of mTORC1 enhanced fraxetin's protective effect. Molecular docking analysis revealed that fraxetin can bind to HEAT-repeats binding site on mTORC1 protein. In  summary, fraxetin pretreatment alleviates CKI by antagonizing autophagy and apoptosis via mTORC1 activation. This provides evidence for the potential therapeutic application of fraxetin in CKI.
    Keywords:  apoptosis; autophagy; cisplatin; fraxetin; mTORC1; renal injury
    DOI:  https://doi.org/10.1002/ptr.8073
  41. Inflammation. 2024 Apr 02.
    VCP Inhibition Augments NLRP3 Inflammasome Activation.
    Ankita Sharma, Dhruva D Dhavale, Paul T Kotzbauer, Conrad C Weihl.
      Lysosomal membrane permeabilization caused either via phagocytosis of particulates or the uptake of protein aggregates can trigger the activation of NLRP3 inflammasome- an intense inflammatory response that drives the release of the pro-inflammatory cytokine IL-1β by regulating the activity of CASPASE 1. The maintenance of lysosomal homeostasis and lysosomal membrane integrity is facilitated by the AAA+ ATPase, VCP/p97 (VCP). However, the relationship between VCP and NLRP3 inflammasome activity remains unexplored. Here, we demonstrate that the VCP inhibitors, DBeQ and ML240 elicit the activation of NLRP3 inflammasome in bone marrow-derived macrophages (BMDMs) when used as activation stimuli. Moreover, genetic inhibition of VCP or VCP chemical inhibition enhances lysosomal membrane damage and augments LLoME-associated NLRP3 inflammasome activation in BMDMs. Similarly, VCP inactivation also augments NLRP3 inflammasome activation mediated by aggregated alpha-synuclein fibrils and lysosomal damage. These data suggest that VCP is a participant in the complex regulation of NLRP3 inflammasome activation.
    Keywords:  ASC speck; Alpha-synuclein fibrils; Bone marrow-derived macrophages; LLoMe; NLRP3 inflammasome; TAT-Cre recombinase.; VCP/p97
    DOI:  https://doi.org/10.1007/s10753-024-02013-6
  42. ACS Infect Dis. 2024 Apr 05.
    MicroRNA-144-3p Inhibits Host Lipid Catabolism and Autophagy by Targeting PPARα and ABCA1 During Mycobacterium Tuberculosis Infection.
    Jing Wu, Yong Zhang, Hao Tang, Bang-Ce Ye.
      MicroRNA-mediated metabolic reprogramming recently has been identified as an important strategy for Mycobacterium tuberculosis (Mtb) to evade host immune responses. However, it is unknown what role microRNA-144-3p (miR-144-3p) plays in cellular metabolism during Mtb infection. Here, we report the meaning of miR-144-3p-mediated lipid accumulation for Mtb-macrophage interplay. Mtb infection was shown to upregulate the expression of miR-144-3p in macrophages. By targeting peroxisome proliferator-activated receptor α (PPARα) and ATP-binding cassette transporter A1 (ABCA1), miR-144-3p overexpression promoted lipid accumulation and bacterial survival in Mtb-infected macrophages, while miR-144-3p inhibition had the opposite effect. Furthermore, reprogramming of host lipid metabolism by miR-144-3p suppressed autophagy in response to Mtb infection. Our findings uncover that miR-144-3p regulates host metabolism and immune responses to Mtb by targeting PPARα and ABCA1, suggesting a potential host-directed tuberculosis therapy by targeting the interface of miRNA and lipid metabolism.
    Keywords:  ABCA1; Mycobacterium tuberculosis; PPARα; autophagy; lipid metabolism; miR-144-3p
    DOI:  https://doi.org/10.1021/acsinfecdis.3c00731
  43. Am J Physiol Cell Physiol. 2024 Apr 01.
    Coculture with Colon-26 cancer cells decreases the protein synthesis rate and shifts energy metabolism towards glycolysis dominance in C2C12 myotubes.
    Yuki Tamura, Karina Kouzaki, Takaya Kotani, Koichi Nakazato.
      Cancer cachexia is the result of complex interorgan interactions initiated by cancer cells and changes in patient behavior such as decreased physical activity and energy intake. Therefore, it is crucial to distinguish between the direct and indirect effects of cancer cells on muscle mass regulation and bioenergetics to identify novel therapeutic targets. In this study, we investigated the direct effects of Colon-26 cancer cells on the molecular regulating machinery of muscle mass and its bioenergetics using a coculture system with C2C12 myotubes. Our results demonstrated that coculture with Colon-26 cells induced myotube atrophy and reduced skeletal muscle protein synthesis and its regulating mammalian target of rapamycin complex 1 signal transduction. However, we did not observe any activating effects on protein degradation pathways including ubiquitin-proteasome and autophagy-lysosome systems. From a bioenergetic perspective, coculture with Colon-26 cells decreased the Complex I-driven, but not Complex II-driven, mitochondrial ATP production capacity, while increasing glycolytic enzyme activity and glycolytic metabolites, suggesting a shift in energy metabolism towards glycolysis dominance. Gene expression profiling by RNA-seq showed that the increased activity of glycolytic enzymes was consistent with changes in gene expression. However, the decreased ATP production capacity of mitochondria was not in line with the gene expression. The potential direct interaction between cancer cells and skeletal muscle cells revealed in this study may contribute to a better fundamental understanding of the complex pathophysiology of cancer cachexia.
    Keywords:  C2C12; cancer cachexia; glycolysis; mitochondria; muscle atrophy
    DOI:  https://doi.org/10.1152/ajpcell.00179.2023
  44. Nitric Oxide. 2024 Apr 03. pii: S1089-8603(24)00045-4. [Epub ahead of print]
    Inflammation-induced sialin mediates nitrate efflux in dysfunctional endothelium affecting NO bioavailability.
    Shamima Akhtar, Komal Sagar, Aishwarya Singh, Milind P Hote, Ambuj Roy, Alpana Sharma.
      AIM: The mechanism of NO bioavailability in endothelial dysfunction, the trigger for atherogenesis is still unclear as exogenous nitrate therapy fails to alleviate endothelial dysfunction. Recently, sialin, a nitrate transporter, has been linked to affect tissue nitrate/nitrite levels. Hence, we investigated the role of sialin in NO bioavailability in endothelial dysfunction.METHODS: Serum-starved HUVECs were stimulated with either TNFα or AT-2 for 24h either alone or in the presence of autophagy inducer or autophagy inhibitor alone. Nitric oxide, nitrite, and nitrate levels were measured in cell supernatant and cell lysate. Quantitative real-time PCR, Annexin V-PI, and monocyte adhesion assays were performed. Immunofluorescence staining for sialin, vWF, and LC3 was performed. STRING database was used to create protein interacting partners for sialin.
    RESULTS: Sialin is strongly expressed in activated EC in vitro and atherosclerotic plaque as well as tumor neo-vessel ECs. Sialin mediates nitrate ion efflux and is negatively regulated by autophagy via mTOR pathway. Blocking sialin enhances NO bioavailability, autophagy, cell survival, and eNOS expression while decreasing monocyte adhesion. PPI shows LGALS8 to directly interact with sialin and regulate autophagy, cell-cell adhesion, and apoptosis.
    CONCLUSION: Sialin is a potential novel therapeutic target for treating endothelial dysfunction in atherosclerosis and cancer.
    Keywords:  Atherosclerosis; Autophagy; Endothelial dysfunction; LGALS8; Nitrate ions; Nitric oxide; Sialin (SLC17A5)
    DOI:  https://doi.org/10.1016/j.niox.2024.04.002
  45. Circ Heart Fail. 2024 Apr 03. e011110
    mTOR Inhibition Prolongs Survival and Has Beneficial Effects on Heart Function After Onset of Lamin A/C Gene Mutation Cardiomyopathy in Mice.
    Wei Wu, Qi Jin, Cecilia Östlund, Kurenai Tanji, Ji-Yeon Shin, Jiying Han, Cheng-Shiun Leu, Jared Kushner, Howard J Worman.
      BACKGROUND: Mutations in LMNA encoding nuclear envelope proteins lamin A/C cause dilated cardiomyopathy. Activation of the AKT/mTOR (RAC-α serine/threonine-protein kinase/mammalian target of rapamycin) pathway is implicated as a potential pathophysiologic mechanism. The aim of this study was to assess whether pharmacological inhibition of mTOR signaling has beneficial effects on heart function and prolongs survival in a mouse model of the disease, after onset of heart failure.METHODS: We treated male LmnaH222P/H222P mice, after the onset of heart failure, with placebo or either of 2 orally bioavailable mTOR inhibitors: everolimus or NV-20494, a rapamycin analog highly selective against mTORC1. We examined left ventricular remodeling, and the cell biological, biochemical, and histopathologic features of cardiomyopathy, potential drug toxicity, and survival.
    RESULTS: Everolimus treatment (n=17) significantly reduced left ventricular dilatation and increased contractility on echocardiography, with a 7% (P=0.018) reduction in left ventricular end-diastolic diameter and a 39% (P=0.0159) increase fractional shortening compared with placebo (n=17) after 6 weeks of treatment. NV-20494 treatment (n=15) yielded similar but more modest and nonsignificant changes. Neither drug prevented the development of cardiac fibrosis. Drug treatment reactivated suppressed autophagy and inhibited mTORC1 signaling in the heart, although everolimus was more potent. With regards to drug toxicity, everolimus alone led to a modest degree of glucose intolerance during glucose challenge. Everolimus (n=20) and NV-20494 (n=20) significantly prolonged median survival in LmnaH222P/H222P mice, by 9% (P=0.0348) and 11% (P=0.0206), respectively, compared with placebo (n=20).
    CONCLUSIONS: These results suggest that mTOR inhibitors may be beneficial in patients with cardiomyopathy caused by LMNA mutations and that further study is warranted.
    Keywords:  cardiomyopathies; everolimus; lamins; mice; nuclear envelope
    DOI:  https://doi.org/10.1161/CIRCHEARTFAILURE.123.011110
  46. Methods Mol Biol. 2024 Apr 06.
    Characterization of Bitter Taste Receptor-Dependent Autophagy in Oral Epithelial Cells.
    Nisha Singh, Saeid Ghavami, Prashen Chelikani.
      Microbial dysbiosis is an important trigger in the development of oral diseases. Oral keratinocytes or gingival epithelial cells (GECs) offer protection against various microbial insults. Recent studies suggest that GECs expressed higher level of bitter taste receptor 14 (T2R14) compared to other taste receptors and toll-like receptors and act as innate immune sentinels. Macroautophagy or autophagy is a cellular conserved process involved in the regulation of host innate immune responses against microbial infection. Here, we describe a robust method for evaluation of T2R14-dependent autophagy flux in GECs. Autophagy flux was detected using Western blot analysis in GECs and further was confirmed using Acridine Orange-dependent flow cytometry analysis.
    Keywords:  Acridine Orange; Autophagosome; Autophagy flux inhibition; Bitter taste receptor; Flow cytometry; Oral epithelial cells; Serum starvation; Western blot
    DOI:  https://doi.org/10.1007/7651_2024_531
  47. Cancer Biol Ther. 2024 Dec 31. 25(1): 2334463
    NRSN2 promotes the malignant behavior of HPV-transfected laryngeal carcinoma cells through AMPK/ULK1 pathway mediated autophagy activation.
    Fan Guo, Wulin Wen, Zhipeng Mi, Chao Long, Qiangyou Shi, Meihua Yang, Jia Zhao, Ruixia Ma.
      Neurensin-2 (NRSN2) performs a pro-carcinogenic function in multiple cancers. However, the function of NRSN2 in HPV-infected laryngeal carcinoma (LC) remains unclear. HPV transfection was performed in LC cells. The mRNA and protein levels were monitored using RT-qPCR, immunoblotting, and IF. Cell viability and proliferation were found using the CCK-8 assay and Edu staining. Cell invasion, migration, and apoptosis were probed using the Transwell, wound healing, and flow cytometry, respectively. The autophagosome was observed using TEM. NRSN2 was overexpressed in HPV-transfected LC cells. Inhibition of NRSN2 restrained the autophagy and malignant behavior of HPV-transfected LC cells. Meanwhile, the inhibition of AMPK/ULK1 pathway limited the increased autophagy of HPV-transfected LC cells caused by NRSN2 overexpression. Furthermore, NRSN2 knockdown inhibits autophagy by suppressing AMPK/ULK1 pathway, thereby restraining the malignant behavior of HPV-transfected LC cells. Our research confirmed that HPV transfection increased the autophagy and malignant behavior of LC cells by regulating the NRSN2-mediated activation of the AMPK/ULK1 pathway, offering a new target for cure of LC.
    Keywords:  AMPK/ULK1 pathway; HPV; Laryngeal carcinoma; NRSN2; autophagy
    DOI:  https://doi.org/10.1080/15384047.2024.2334463
  48. Cell Commun Signal. 2024 Apr 03. 22(1): 215
    Gut microbiota-derived butyrate restores impaired regulatory T cells in patients with AChR myasthenia gravis via mTOR-mediated autophagy.
    Long He, Zhuotai Zhong, Shuting Wen, Peiwu Li, Qilong Jiang, Fengbin Liu.
      More than 80% of patients with myasthenia gravis (MG) are positive for anti-acetylcholine receptor (AChR) antibodies. Regulatory T cells (Tregs) suppress overproduction of these antibodies, and patients with AChR antibody-positive MG (AChR MG) exhibit impaired Treg function and reduced Treg numbers. The gut microbiota and their metabolites play a crucial role in maintaining Treg differentiation and function. However, whether impaired Tregs correlate with gut microbiota activity in patients with AChR MG remains unknown. Here, we demonstrate that butyric acid-producing gut bacteria and serum butyric acid level are reduced in patients with AChR MG. Butyrate supplementation effectively enhanced Treg differentiation and their suppressive function of AChR MG. Mechanistically, butyrate activates autophagy of Treg cells by inhibiting the mammalian target of rapamycin. Activation of autophagy increased oxidative phosphorylation and surface expression of cytotoxic T-lymphocyte-associated protein 4 on Treg cells, thereby promoting Treg differentiation and their suppressive function in AChR MG. This observed effect of butyrate was blocked using chloroquine, an autophagy inhibitor, suggesting the vital role of butyrate-activated autophagy in Tregs of patients with AChR MG. We propose that gut bacteria derived butyrate has potential therapeutic efficacy against AChR MG by restoring impaired Tregs.
    Keywords:  Autophagy; Butyrate; Gut microbiota; Myasthenia gravis; Treg
    DOI:  https://doi.org/10.1186/s12964-024-01588-9
  49. Oncogene. 2024 Apr 02.
    USP26 promotes colorectal cancer tumorigenesis by restraining PRKN-mediated mitophagy.
    Qi Wu, Zhihong Wang, Siqi Chen, Xiaowei She, Shengyu Zhu, Pengcheng Li, Lang Liu, Chongchong Zhao, Kangdi Li, Anyi Liu, Changsheng Huang, Yaqi Chen, Fuqing Hu, Guihua Wang, Junbo Hu.
      Deubiquitinating enzymes (DUBs) are promising targets for cancer therapy because of their pivotal roles in various physiological and pathological processes. Among these, ubiquitin-specific peptidase 26 (USP26) is a protease with crucial regulatory functions. Our study sheds light on the upregulation of USP26 in colorectal cancer (CRC), in which its increased expression correlates with an unfavorable prognosis. Herein, we evidenced the role of USP26 in promoting CRC tumorigenesis in a parkin RBR E3 ubiquitin-protein ligase (PRKN) protein-dependent manner. Our investigation revealed that USP26 directly interacted with PRKN protein, facilitating its deubiquitination, and subsequently reducing its activity. Additionally, we identified the K129 site on PRKN as a specific target for USP26-mediated deubiquitination. Our research highlights that a K-to-R mutation at the site on PRKN diminishes its potential for activation and ability to mediate mitophagy. In summary, our findings underscore the significance of USP26-mediated deubiquitination in restraining the activation of the PRKN-mediated mitophagy pathway, ultimately driving CRC tumorigenesis. This study not only elucidated the multifaceted role of USP26 in CRC but also introduced a promising avenue for therapeutic exploration through the development of small molecule inhibitors targeting USP26. This strategy holds promise as a novel therapeutic approach for CRC.
    DOI:  https://doi.org/10.1038/s41388-024-03009-0
  50. Heliyon. 2024 Mar 30. 10(6): e28406
    Interplay of p62-mTORC1 and EGFR signaling promotes cisplatin resistance in oral cancer.
    Hsiu-Chuan Chang, Cheng-Chieh Yang, Lai-Keng Loi, Chi-Hsun Hung, Cheng-Hsien Wu, Yu-Cheng Lin.
      Cisplatin resistance poses a major challenge in the treatment of oral squamous cell carcinoma (OSCC). Deeper investigations into the mechanisms underlying this drug resistance is of great importance. Here, we used cellular assays and clinical immunohistochemistry to examine molecular pathways involved in both innate and acquired cisplatin resistance. We demonstrated that the p62-mTORC1 signaling complex plays a pivotal role, and is driven by the EGFR signaling network, specifically through the PI3K-Akt axis and the transcription factor C/EBP-β. Elevated p-mTOR expression was associated with cancer relapse and poor prognosis among oral cancer patients. Additionally, we illustrated that mTOR inhibitors enhance the cytotoxic effect of cisplatin, by employing cancer stem cell characteristics. Our work unveils fundamental mechanisms for cisplatin resistance, thereby presenting therapeutic implications for OSCC.
    Keywords:  Cisplatin resistance; EGFR; OSCC; mTOR; p62
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e28406
  51. J Cell Mol Med. 2024 Apr;28(8): e18051
    PGC-1α regulates the interplay between oxidative stress, senescence and autophagy in the ageing retina important in age-related macular degeneration.
    Iswariyaraja Sridevi Gurubaran, Cezary Watala, Joanna Kostanek, Joanna Szczepanska, Elzbieta Pawlowska, Kai Kaarniranta, Janusz Blasiak.
      We previously showed that mice with knockout in the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) gene encoding the PGC-1α protein, and nuclear factor erythroid 2 like 2 (NFE2L2) gene, exhibited some features of the age-related macular degeneration (AMD) phenotype. To further explore the mechanism behind the involvement of PGC-1α in AMD pathogenesis we used young (3-month) and old (12-month) mice with knockout in the PPARGC1A gene and age-matched wild-type (WT) animals. An immunohistochemical analysis showed age-dependent different expression of markers of oxidative stress defence, senescence and autophagy in the retinal pigment epithelium of KO animals as compared with their WT counterparts. Multivariate inference testing showed that senescence and autophagy proteins had the greatest impact on the discrimination between KO and WT 3-month animals, but proteins of antioxidant defence also contributed to that discrimination. A bioinformatic analysis showed that PGC-1α might coordinate the interplay between genes encoding proteins involved in antioxidant defence, senescence and autophagy in the ageing retina. These data support importance of PGC-1α in AMD pathogenesis and confirm the utility of mice with PGC-1α knockout as an animal model to study AMD pathogenesis.
    Keywords:  AMD; PGC‐1α; ageing retina; age‐related macular degeneration; autophagy; cellular senescence; oxidative stress; peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha
    DOI:  https://doi.org/10.1111/jcmm.18051
  52. CNS Neurosci Ther. 2024 Apr;30(4): e14703
    SIRT3 alleviates painful diabetic neuropathy by mediating the FoxO3a-PINK1-Parkin signaling pathway to activate mitophagy.
    Jing Yang, Zhuoying Yu, Ye Jiang, Zixian Zhang, Yue Tian, Jie Cai, Min Wei, Yanhan Lyu, Dongsheng Yang, Shixiong Shen, Guo-Gang Xing, Min Li.
      INTRODUCTION: Painful diabetic neuropathy (PDN) is a common complication of diabetes. Previous studies have implicated that mitochondrial dysfunction plays a role in the development of PDN, but its pathogenesis and mechanism have not been fully investigated.METHODS: In this study, we used high-fat diet/low-dose streptozotocin-induced rats as a model of type 2 diabetes mellitus. Behavioral testing, whole-cell patch-clamp recordings of dorsal root ganglion (DRG) neurons, and complex sensory nerve conduction velocity studies were used to assess peripheral neuropathy. Mitochondrial membrane potential (MMP), ATP, tissue reactive oxygen species, and transmission electron microscopy were used to evaluate the function and morphology of mitochondria in DRG. Real-time PCR, western blot, and immunofluorescence were performed to investigate the mechanism.
    RESULTS: We found that damaged mitochondria were accumulated and mitophagy was inhibited in PDN rats. The expression of sirtuin 3 (SIRT3), which is an NAD+-dependent deacetylase in mitochondria, was inhibited. Overexpression of SIRT3 in DRG neurons by intrathecally administered LV-SIRT3 lentivirus ameliorated neurological and mitochondrial dysfunctions. This was evidenced by the reversal of allodynia and nociceptor hyperexcitability, as well as the restoration of MMP and ATP levels. Overexpression of SIRT3 restored the inhibited mitophagy by activating the FoxO3a-PINK1-Parkin signaling pathway. The effects of SIRT3 overexpression, including the reversal of allodynia and nociceptor hyperexcitability, the improvement of impaired mitochondria and mitophagy, and the restoration of PINK1 and Parkin expression, were counteracted when FoxO3a siRNA was intrathecally injected.
    CONCLUSION: These results showed that SIRT3 overexpression ameliorates PDN via activation of FoxO3a-PINK1-Parkin-mediated mitophagy, suggesting that SIRT3 may become an encouraging therapeutic strategy for PDN.
    Keywords:  SIRT3; dorsal root ganglion; mitochondria; mitophagy; painful diabetic neuropathy
    DOI:  https://doi.org/10.1111/cns.14703
  53. Transl Neurodegener. 2024 Apr 02. 13(1): 17
    Dietary fasting and time-restricted eating in Huntington's disease: therapeutic potential and underlying mechanisms.
    Russell G Wells, Lee E Neilson, Andrew W McHill, Amie L Hiller.
      Huntington's disease (HD) is a devastating neurodegenerative disorder caused by aggregation of the mutant huntingtin (mHTT) protein, resulting from a CAG repeat expansion in the huntingtin gene HTT. HD is characterized by a variety of debilitating symptoms including involuntary movements, cognitive impairment, and psychiatric disturbances. Despite considerable efforts, effective disease-modifying treatments for HD remain elusive, necessitating exploration of novel therapeutic approaches, including lifestyle modifications that could delay symptom onset and disease progression. Recent studies suggest that time-restricted eating (TRE), a form of intermittent fasting involving daily caloric intake within a limited time window, may hold promise in the treatment of neurodegenerative diseases, including HD. TRE has been shown to improve mitochondrial function, upregulate autophagy, reduce oxidative stress, regulate the sleep-wake cycle, and enhance cognitive function. In this review, we explore the potential therapeutic role of TRE in HD, focusing on its underlying physiological mechanisms. We discuss how TRE might enhance the clearance of mHTT, recover striatal brain-derived neurotrophic factor levels, improve mitochondrial function and stress-response pathways, and synchronize circadian rhythm activity. Understanding these mechanisms is critical for the development of targeted lifestyle interventions to mitigate HD pathology and improve patient outcomes. While the potential benefits of TRE in HD animal models are encouraging, future comprehensive clinical trials will be necessary to evaluate its safety, feasibility, and efficacy in persons with HD.
    Keywords:  Autophagy; Circadian rhythm; Dietary fasting; Huntington’s disease; Intermittent fasting; Lifestyle intervention; Mitochondrial biogenesis; Neuroprotection; Time-restricted eating
    DOI:  https://doi.org/10.1186/s40035-024-00406-z
  54. FEBS J. 2024 Apr 03.
    Role of mitochondria in renal ischemia-reperfusion injury.
    Ruizhen Huang, Chiyu Zhang, Zhengjie Xiang, Tao Lin, Jian Ling, Honglin Hu.
      Acute kidney injury (AKI) induced by renal ischemia-reperfusion injury (IRI) has a high morbidity and mortality, representing a worldwide problem. The kidney is an essential organ of metabolism that has high blood perfusion and is the second most mitochondria-rich organ after the heart because of the high ATP demands of its essential functions of nutrient reabsorption, acid-base and electrolyte balance, and hemodynamics. Thus, these energy-intensive cells are particularly vulnerable to mitochondrial dysfunction. As the bulk of glomerular ultrafiltrate reabsorption by proximal tubules occurs via active transport, the mitochondria of proximal tubules must be equipped for detecting and responding to fluctuations in energy availability to guarantee efficient basal metabolism. Any insults to mitochondrial quality control mechanisms may lead to biological disruption, blocking the clearance of damaged mitochondria and resulting in morphological change and tissue dysfunction. Extensive research has shown that mitochondria have pivotal roles in acute kidney disease, so in this article, we discuss the role of mitochondria, their dynamics and mitophagy in renal ischemia-reperfusion injury.
    Keywords:  mitochondrial dynamics; mitochondrial fission; mitochondrial fusion; mitophagy; renal ischemia–reperfusion injury
    DOI:  https://doi.org/10.1111/febs.17130
  55. Neuropathol Appl Neurobiol. 2024 Apr;50(2): e12974
    Targeting the EGFR pathway: An alternative strategy for the treatment of tuberous sclerosis complex?
    Julia Schachenhofer, Victoria-Elisabeth Gruber, Stefanie Valerie Fehrer, Carmen Haider, Sarah Glatter, Ewa Liszewska, Romana Höftberger, Eleonora Aronica, Karl Rössler, Jacek Jaworski, Theresa Scholl, Martha Feucht.
      INTRODUCTION: Tuberous sclerosis complex (TSC) is caused by variants in TSC1/TSC2, leading to constitutive activation of the mammalian target of rapamycin (mTOR) complex 1. Therapy with everolimus has been approved for TSC, but variations in success are frequent. Recently, caudal late interneuron progenitor (CLIP) cells were identified as a common origin of the TSC brain pathologies such as subependymal giant cell astrocytomas (SEGA) and cortical tubers (CT). Further, targeting the epidermal growth factor receptor (EGFR) with afatinib, which is expressed in CLIP cells, reduces cell growth in cerebral TSC organoids. However, investigation of clinical patient-derived data is lacking.AIMS: Observation of EGFR expression in SEGA, CT and focal cortical dysplasia (FCD) 2B human brain specimen and investigation of whether its inhibition could be a potential therapeutic intervention for these patients.
    METHODS: Brain specimens of 23 SEGAs, 6 CTs, 20 FCD2Bs and 17 controls were analysed via immunohistochemistry to characterise EGFR expression, cell proliferation (via Mib1) and mTOR signalling. In a cell-based assay using primary patient-derived cells (CT n = 1, FCD2B n = 1 and SEGA n = 4), the effects of afatinib and everolimus on cell proliferation and cell viability were observed.
    RESULTS: EGFR overexpression was observed in histological sections of SEGA, CT and FCD2B patients. Both everolimus and afatinib decreased the proliferation and viability in primary SEGA, tuber and FCD2B cells.
    CONCLUSION: Our study demonstrates that EGFR suppression might be an effective alternative treatment option for SEGAs and tubers, as well as other mTOR-associated malformations of cortical development, including FCD2B.
    Keywords:  EGFR; SEGA; TSC; afatinib; focal cortical dysplasia; tuber; tuberous sclerosis complex
    DOI:  https://doi.org/10.1111/nan.12974
  56. bioRxiv. 2024 Mar 20. pii: 2024.03.18.585556. [Epub ahead of print]
    Ibudilast Protects Retinal Bipolar Cells from Excitotoxic Retinal Damage and Activates the mTOR Pathway.
    Sumaya Hamadmad, Tyler Heisler-Taylor, Sandeep Goswami, Evan Hawthorn, Sameer Chaurasia, Dena Martini, Diana Summitt, Ali Zaatari, Elizabeth G Urbanski, Kayla Bernstein, Julie Racine, Abhay Satoskar, Heithem M El-Hodiri, Andy J Fischer, Colleen M Cebulla.
      Ibudilast, an inhibitor of macrophage migration inhibitory factor (MIF) and phosphodiesterase (PDE), has been recently shown to have neuroprotective effects in a variety of neurologic diseases. We utilize a chick excitotoxic retinal damage model to investigate ibudilast's potential to protect retinal neurons. Using single cell RNA-sequencing (scRNA-seq), we find that MIF, putative MIF receptors CD74 and CD44, and several PDEs are upregulated in different retinal cells during damage. Intravitreal ibudilast is well tolerated in the eye and causes no evidence of toxicity. Ibudilast effectively protects neurons in the inner nuclear layer from NMDA-induced cell death, restores retinal layer thickness on spectral domain optical coherence tomography, and preserves retinal neuron function, particularly for the ON bipolar cells, as assessed by electroretinography. PDE inhibition seems essential for ibudilast's neuroprotection, as AV1013, the analogue that lacks PDE inhibitor activity, is ineffective. scRNA-seq analysis reveals upregulation of multiple signaling pathways, including mTOR, in damaged Müller glia (MG) with ibudilast treatment compared to AV1013. Components of mTORC1 and mTORC2 are upregulated in both bipolar cells and MG with ibudilast. The mTOR inhibitor rapamycin blocked accumulation of pS6 but did not reduce TUNEL positive dying cells. Additionally, through ligand-receptor interaction analysis, crosstalk between bipolar cells and MG may be important for neuroprotection. We have identified several paracrine signaling pathways that are known to contribute to cell survival and neuroprotection and might play essential roles in ibudilast function. These findings highlight ibudilast's potential to protect inner retinal neurons during damage and show promise for future clinical translation.
    DOI:  https://doi.org/10.1101/2024.03.18.585556
  57. Biochem Biophys Res Commun. 2024 Mar 27. pii: S0006-291X(24)00378-4. [Epub ahead of print]709 149842
    Combination treatment with ferroptosis and autophagy inducers significantly inhibit the proliferation and migration of oral squamous cell carcinoma.
    Lei Zhang, Zhijia Li, Xue Ma, Wenwen Yang, Yacui Hao, Lan Zhang, Songlin Piao.
      Oral squamous cell carcinoma (OSCC), a malignancy originating from mucosal epithelial cells. Currently, triggering apoptotic cell death with anticancer drugs is the main way to inhibit OSCC cells. However, the capability to trigger apoptosis in tumors is constrained by the intrinsic resistance of tumor cells to apoptosis, hampering its effectiveness. Thus, utilizing alternative modes of non-apoptotic cell death offers new therapeutic possibilities, such as using a drug combination strategy to simultaneously induce ferroptosis and autophagy has the potential to improve OSCC therapy. In this study, we found the ferroptosis inducer RSL3 has certain inhibitory effects on the proliferation and migration of OSCC cells. Interestingly, our studies showed that RSL3 is also associated with autophagy activation. Based on this finding, we tried to combine RSL3 with the autophagy inducer LYN-1604 to improve the therapeutic effect. The results demonstrated that simultaneous regulation of autophagy and ferroptosis significantly reduced the proliferation and migration of OSCC cells. Taken together, we demonstrated the therapeutic potential of RSL3 in OSCC cells and proposed that simultaneous activation of autophagy and ferroptosis have synergistic effects, which would provide valuable clues for further exploration of targeted therapy for OSCC.
    Keywords:  Autophagy; Combination treatment; Ferroptosis; Oral squamous cell carcinoma (OSCC); RSL3
    DOI:  https://doi.org/10.1016/j.bbrc.2024.149842
  58. iScience. 2024 Apr 19. 27(4): 109321
    AP39 through AMPK-ULK1-FUNDC1 pathway regulates mitophagy, inhibits pyroptosis, and improves doxorubicin-induced myocardial fibrosis.
    Junxiong Zhao, Ting Yang, Jiali Yi, Hongmin Hu, Qi Lai, Liangui Nie, Maojun Liu, Chun Chu, Jun Yang.
      Doxorubicin induces myocardial injury and fibrosis. Still, no effective interventions are available. AP39 is an H2S donor that explicitly targets mitochondria. This study investigated whether AP39 could improve doxorubicin-induced myocardial fibrosis. Doxorubicin induced significant myocardial fibrosis while suppressing mitophagy-related proteins and elevating pyroptosis-related proteins. Conversely, AP39 reverses these effects, enhancing mitophagy and inhibiting pyroptosis. In vitro experiments revealed that AP39 inhibited H9c2 cardiomyocyte pyroptosis, improved doxorubicin-induced impairment of mitophagy, reduced ROS levels, ameliorated the mitochondrial membrane potential, and upregulated AMPK-ULK1-FUNDC1 expression. In contrast, AMPK inhibitor (dorsomorphin) and ULK1 inhibitor (SBI-0206965) reversed AP39 antagonism of doxorubicin-induced FUNDC1-mediated impairment of mitophagy and secondary cardiomyocyte pyroptosis. These results suggest that mitochondria-targeted H2S can antagonize doxorubicin-induced pyroptosis and impaired mitophagy in cardiomyocytes via AMPK-ULK1-FUNDC1 and ameliorated myocardial fibrosis and remodeling.
    Keywords:  Health sciences; Toxic substance; Toxicology
    DOI:  https://doi.org/10.1016/j.isci.2024.109321
  59. Drug Discov Ther. 2024 Apr 04.
    Rapamycin vs TORin-1 or Gleevec vs Nilotinib: Simple chemical evolution that converts PAK1-blockers to TOR-blockers or vice versa?
    Hiroshi Maruta, Hong He.
      Both PAK1 (RAC/CDC42-activating kinase 1) and TOR (Target of Rapamycin) are among the major oncogenic/ageing kinases. However, they play the opposite role in our immune system, namely immune system is suppressed by PAK1, while it requires TOR. Thus, PAK1-blockers, would be more effective for therapy of cancers, than TOR-blockers. Since 2015 when we discovered genetically that PDGF-induced melanogenesis depends on "PAK1", we are able to screening a series of PAK1-blockers as melanogenesis-inhibitors which could eventually promote longevity. Interestingly, rapamycin, the first TOR-inhibitor, promotes melanogenesis, clearly indicating that TOR suppresses melanogenesis. However, a new TOR-inhibitor called TORin-1 no longer suppresses immune system, and blocks melanogenesis in cell culture. These observations strongly indicate that TORin-1 acts as PAK1-blockers, instead of TOR-blockers, in vivo. Thus, it is most likely that melanogenesis in cell culture could enable us to discriminate PAK1-blockers from TORblockers.
    Keywords:  Gleevec; PAK1; TOR; TORin-1; immune system; melanogenesis; nilotinib; rapamycin
    DOI:  https://doi.org/10.5582/ddt.2023.01097
This page is being maintained by Thomas Krichel. It was last updated on 2024‒04‒07 at 10:01.